14_leechengxu2012.pdf
TRANSCRIPT
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UNIVERSITI TEKNOLOGI MALAYSIA
NOTES : * If the thesis is CONFIDENTAL or RESTRICTED, please attach with the
letter from the organization with period and reasons for confidentiality
or restriction.
DECLARATION OF THESIS / UNDERGRADUATE PROJECT PAPER AND COPYRIGHT
Author’s full name : LEE CHENGXU
Date of birth : 16 MARCH 1988
Title : DESIGN OF PLASMA NEEDLE AND HIGH FREQUENCY
POWER SUPPLY FOR BIO-MEDICAL APPLICATIONS
Academic Session : 2011/2012
I declare that this thesis is classified as :
CONFIDENTIAL (Contains confidential information under the
Official Secret Act 1972)*
RESTRICTED (Contains restricted information as specified by
the organization where research was done)*
OPEN ACCESS I agree that my thesis to be published as online
open access (full text)
I acknowledged that Universiti Teknologi Malaysia reserves the right as follows :
1. The thesis is the property of Universiti Teknologi Malaysia.
2. The Library of Universiti Teknologi Malaysia has the right to make copies for
the purpose of research only.
3. The Library has the right to make copies of the thesis for academic
exchange.
Certified by:
SIGNATURE SIGNATURE OF SUPERVISOR
880316-02-5377
ASSOC. PROF. DR. ZOLKAFLE BUNTAT
(NEW IC NO. /PASSPORT NO.) NAME OF SUPERVISOR
Date : 27th JUNE 2012 Date : 27th JUNE 2012
√
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“I hereby declared that I have read this thesis and in my
opinion this thesis is sufficient in terms of scope and quality for the
award of Bachelor of Engineering (Electrical).”
Signature :
Name of Supervisor : ASSOC. PROF. DR. ZOLKAFLE BUNTAT
Date : 27th
JUNE 2012
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DESIGN OF PLASMA NEEDLE AND HIGH FREQUENCY POWER
SUPPLY FOR BIO-MEDICAL APPLICATIONS
LEE CHENGXU
This report is submitted in partial fulfillment of the
requirements for the award of the degree of
Bachelor of Engineering (Electrical)
Faculty of Electrical Engineering
Universiti Teknologi Malaysia
JUNE 2012
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I declare that this thesis entitled “Design of Plasma Needle and High Frequency
Power Supply for Bio-Medical Applications” is the result of my own research except
as cited in the references. The thesis has not been accepted for any degree and is not
concurrently submitted in candidature of any other degree.
Signature :
Name : LEE CHENGXU
Date : 27th
JUNE 2012
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Dedicated to my beloved father and mother, siblings, friends and lecturers for their
endless loves, encouragement and support
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ACKNOWLEDGEMENT
First of all, I would like to express my heartiest gratitude to my supervisor,
Assoc. Prof. Dr. Zolkafle Buntat for his professional guidance, comments and
endless inspirations in the preparation of this research from scratch to successfully
accomplish. I appreciated that I can still seek for his help, advices and suggestions
while in the middle of his busyness. Besides, I would like to thank Dr. Muhammad
Abu Bakar Sidik for his guidance and help as well.
My deepest appreciation goes to my family, friends, fellow course mates and
laboratory technicians for their endless love, endurance and support during the entire
research process. Last but not least, I would like to thank those who directly and
indirectly contribute in making this research a success.
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ABSTRACT
Non-thermal plasma treatment of living tissues has become a popular topic in
medical sciences after it was discovered to have the bacteria inactivation function in
year 2002. It is generated under atmospheric pressure and room temperature by
radio-frequent excitation. At the moment, commercialized research function
generator and amplifier are used to generate the non-thermal plasma. Hence, the cost
for current high frequency power supply is very expensive and unfeasible to be used
widely in bio-medical applications. Hence, a cheaper high frequency power supply
should be developed for future applications. Besides, the generated plasma at the tip
of the current plasma needle also very small. It needs a longer treatment time if it is
being applied on a larger wound. In this work, a high frequency power supply for
non-thermal plasma source was designed and developed by using modified class-E
power amplifier circuit. MAX038 was used as signal generator to generate the high
frequency signal. MOSFET Driver DEIC515 and MOSFET DE275X2-102N06A
were used for ultra-fast switching before attached to the amplifier circuit. Based on
the simulation, the designed high frequency power supply has the capability of
generating 505Vpp at frequency of 13.56MHz and this output is high enough to
generate the non-thermal plasma. A novel design of plasma needle with a ring
magnet at the head of the needle was designed with the aims to improve the plasma
uniformity as well as increasing the healing effects on the treated area. Besides high
frequency power supply, this report will present the enhancement design of plasma
needle as well. Some recommendations for future research also being included in the
final part of the report.
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ABSTRAK
Baru-baru ini, rawatan plasma sejuk pada tisu hidup telah menjadi satu topic
yang popular dalam bidang sains perubatan selepas ia ditemui mempunyai fungsi
penghapusan bakteria pada tahun 2002. Ia dihasilkan di bawah tekanan atmosfera
dan suhu bilik oleh getaran frekuensi radio. Pada masa ini, penjana dan penguat yang
dikomersialkan untuk tujuan penyelidikan telah digunakan untuk menjana plasma
sejuk. Oleh itu, penjana kuasa berfrekuensi tinggi yang lebih murah perlu direkacipta
untuk aplikasi pada masa depan.Selain itu, saiz plasma yang dijana pada hujung
jarum plasma juga sangat kecil. Ia memerlukan masa rawatan yang lebih panjang jika
digunakan pada luka yang saiznya lebih besar. Dalam karya ini, penjana kuasa yang
berfrekuensi tinggi telah direka dan dibangunkan dengan menggunakan litar penguat
kuasa kelas E yang telah diubahsuai. MAX038 telah digunakan sebagai penjana
isyarat untuk menjana isyarat berfrekuensi tinggi. Pemandu MOSFET DEIC515 dan
MOSFET DE275X2,-102N06A telah digunakan untuk tujuan pensuisan ultra-cepat
sebelum dipasang pada litar penguat. Berdasarkan simulasi yang telah dibuat, rekaan
penjana kuasa frekuensi tinggi ini mampu menjana 505Vpp pada frekuensi
13.56MHz dan keluaran ini adalah cukup tinggi untuk menjana plasma sejuk. Reka
bentuk baru jarum plasma dengan magnet cincin di kepala jarum telah direka
bertujuan untuk meningkatkan keseragaman plasma serta meningkatkan kesan
penyembuhan pada kawasan yang dirawat. Selain penjana kuasa frekuensi tinggi,
laporan ini juga akan membentangkan jarum plasma yang direka. Beberapa cadangan
untuk kajian pada masa hadapan juga dimasukkan dalam bahagian akhir laporan ini.
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TABLE OF CONTENTS
CHAPTER TITLE PAGE
DECLARATION
ii
DEDICATION iii
ACKNOWLEDGEMENTS iv
ABSTRACT v
ABSTRAK vi
TABLE OF CONTENTS vii
LIST OF FIGURES x
LIST OF SYMBOLS xii
LIST OF ABBREVIATIONS xiii
LIST OF APPENDICES xiv
1 INTRODUCTION
1.1 Introduction 1
1.2 Background 1
1.3 Problem Statement 3
1.4 Objectives 4
1.5 Scope of the Project 5
1.6 Significance of the Study 5
2 LITERATURE REVIEW
2.1 Introduction 6
2.2 Plasma Generation 6
2.3 Plasma Needle 7
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2.4 Design of Plasma Needle 10
2.5 Class E Amplifier as RF Plasma Source 11
2.6 45MHz MOSFET Driver 14
2.7 MOSFET 17
2.7.1 MOSFET Turn-on Phenomena 18
2.7.2 MOSFET Turn-off Phenomena 21
2.8 Magnetic Effects on Living Organism 22
2.9 Application of Plasma Needle 23
2.9.1 Dental Applications 23
2.9.2 Plasma Treatment on Mammalian Vascular
Cells
24
2.9.3 Cancer Treatment 24
3 RESEARCH METHODOLOGY
3.1 Introduction 25
3.2 Methodology Procedure 26
3.3 Related Guidelines and Datasheets 27
3.4 Software Used for Modelling 27
3.4.1 SolidWorks 2011 27
3.4.2 Multisim 10.0 29
4 PLASMA NEEDLE DESIGN
4.1 Introduction 30
4.2 Modelling Components 30
4.3 Modelling Dimensions 31
4.4 Modelling Descriptions 32
5 HIGH FREQUENCY POWER SUPPLY
5.1 Introduction 35
5.2 Simulation Development 35
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5.2.1 Simulation of Modified Class E Amplifier 36
5.3 Hardware Development 37
5.3.1 MAX038 Frequency Waveform Generator 38
5.3.2 DEIC515 MOSFET Driver Circuit 39
5.3.3 DEIC515 and DE275X2-102N06A MOSFET
Circuit
40
6 RESULTS AND DISCUSSIONS
6.1 Introduction 42
6.2 Simulation Results for Modified Class E Amplifier 42
6.3 Hardware Results 44
6.3.1 MAX038 Frequency Waveform Generator 44
6.3.2 DEIC515 MOSFET Driver 45
6.3.3 DEIC515 and DE275X2-102N06A MOSFET 47
7 CONCLUSION AND RECOMMENDATION
7.1 Introduction 49
7.2 Conclusion 49
7.3 Recommendation 50
REFERENCES 52
APPENDICES
APPENDIX A 55
APPENDIX B 57
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LIST OF FIGURES
FIGURE NO. TITLE PAGE
1.1 Thermal Plasma 2
2.1 General Schematic of RF Capacitively Coupled
Plasma
7
2.2 Schematic of Plasma Needle Setup 8
2.3 Stability Curves of The Plasma 9
2.4 Plasma Needle 10
2.5 Class E Amplifier Circuit Diagram 12
2.6 Experimental waveform 14
2.7 Symbol and equivalent circuit of a MOSFET 17
2.8 Transfer characteristics of a power MOSFET 18
2.9 A MOSFET being turned on by a driver in a clamped
inductive load
19
2.10 A MOSFET being turned off by a driver in a clamped
inductive load
19
2.11 MOSFET turn on sequence 20
2.12 MOSFET turn off sequence 22
4.1 Components of Plasma Needle 31
4.2 Dimensions of Plasma Needle 31
4.3 Plasma Needle Model 33
4.4 The Pyrex tube moved 5mm into the plastic holder 34
4.5 Plasma Needle after Rendered 35
5.1 Modified Class E Amplifier Simulation Circuit 36
5.2 MAX038 Frequency Waveform Generator Circuit 38
5.3 MAX038 Hardware Circuit 39
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5.4 DEIC515 MOSFET Driver Circuit 39
5.5 DEIC515 Hardware Circuit 40
5.6 DEIC515 and MOSFET Hardware Circuit 41
6.1 Simulated waveform of VCT and VCR 43
6.2 Simulated waveform of Vin and Vo 43
6.3 Output of MAX038 44
6.4 Output of DEIC515 46
6.5 Output of DE275X2-102N06A 48
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LIST OF SYMBOLS
K - Kelvin
0C - Degree Celcius
UV - Ultraviolet
Min - Minute
ns - Nanoseconds
IG - Gate Current
ID - Drain Current
IS - Source Current
V - Volts
kV - Kilo Volts
kΩ - Kilo Ohms
mm - Milimeter
cm - Centimetre
mV - Mili Volts
mW - Mili Watts
GHz - Giga Hertz
MHz - Mega Hertz
Vpp - Peak-to-peak Voltage
Vp - Peak Voltage
He - Helium
uH - Micro Henries
mH - Mili Henries
ZL - Load Impedance
VGS(th) - Threshold Voltage
VCC - Power Supply Voltage
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LIST OF ABBREVIATIONS
RF - Radio Frequency
f - Frequency
BNC - Bayonet Neill–Concelman
DC - Direct Current
AC - Alternating Current
UTM - Universiti Teknologi Malaysia
CCP - Capacitvely Coupled Plasma
NI - National Instrument
OD - Outer Diameter
ID - Internal Diameter
IGBT - Insulated Gate Bipolar Transistor
MOSFET - Metal–oxide–semiconductor Field-effect Transistor
IC - Integrated Circuit
PCB - Printed Circuit Board
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LIST OF APPENDICES
APPENDIX TITLE PAGE
A Apparatus for Hardware Experiment 55
B Datasheet 57
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CHAPTER 1
INTRODUCTION
1.1 Introduction
The conducted research was Design of Plasma Needle and High Frequency
Power Supply for Bio-Medical Applications. The reason this topic was chosen is
because non-thermal plasma treatment has become more and more popular in
modern plasma physics and in medical sciences. Besides, non-thermal plasma has
made an innovative form in solid state processing technology. In this chapter, there
are a few things that will be covered, namely background of the study, problem
statement, objective of the study, scope of the study and significance of the study.
1.2 Background of the Study
On earth, solid, liquid and gas are three states of matter that can be easily
found. Human are very familiar with these three states of matter as they are facing
them everyday. In 1879, an English physicist, Sir William Crookes had identified a
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fourth state of matter where we call it as plasma now. The name plasma was first
being applied by Dr. Irving Langmuir, an American chemist and physicist, in 1929.
Plasma comprises of free charge carriers (electrons and ions), active radicals
and excited molecules and atoms which is similar to gas. High energy such as
thermal, electrical, or light is needed to ionize its atom or molecules and this process
will cause the gas to become electrically conductive. This electrically conductive,
ionized gas is called plasma. The temperature for plasma electrons normally above
104 K while the temperature for neutrals and ions depend on type of plasma and have
the range from room temperature to 107 K.
Plasma can be classified as „thermal‟ and „non-thermal‟ based on their
relative temperatures of the electrons, molecules, ions and atoms. For thermal plasma,
its electrons temperature and gas temperature are in thermodynamic equilibrium. In
other word, the temperature of molecules, ions and atoms are same with the electrons
temperature. Few examples of thermal plasmas are shown in Figure 1.1.
(a) (b)
Figure 1.1: Thermal Plasma (a) Lighning Strike and (b) Metal Spraying
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For non thermal plasma, the electron temperature and gas temperature are not
in equilibrium with each other. The temperature of molecules, ions and atoms are
much lower (normally room temperature) than electrons (higher temperature). The
relative low temperature of non-thermal plasma make it does not impose thermal
damage to nearby object. The thermal damage caused by the high temperature of
thermal plasma has been eliminated or minimised. Since the thermal damage had
been eliminated, it can be applied in many applications.
The current trend is more focus on using non-thermal plasma in bio-medical
applications, usage on living tissues and even usage on human body. Non-thermal
plasma has the capability of bacterial inactivation [1], non-inflammatory tissue
modification [2] and healing effects on a living organism [3][4]. These capabilities
led to the development of the plasma needle and many researchers glow their interest
at the interaction between non-thermal plasmas and biological tissues.
1.3 Problem Statement
The plasma system that researchers are using now is very expensive. This is
because commercialize function generator and research amplifier are used in plasma
radio-frequency (RF) power supply. This equipment is not specifically use for
generating non-thermal plasma but normally used in laboratory with the purpose of
studying and researching. Due to the high cost of the plasma system, alternative for
cheaper RF power supply is needed so that the cost for plasma system can be
lowered down. This is vital for future applications of non-thermal plasma.
One of the applications for non-thermal plasma is plasma needle which
introduced by Eva Stoffels in 2002 [5]. The generated plasma is non-thermal plasma
where the temperature of the molecules, ions and atoms is about room temperature
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and operates at atmospheric pressure. These characteristics open the opportunity of
using plasma needle in biomedical fields and even on human body. However, plasma
that is generated by plasma needle setup is very small (about one milimeter in
diameter). Due to this reason, the treatment time will be prolonged when the
treatment area is enormous.
It is proven that non-thermal plasma has the healing effects on a living
organism [3]. Medical research states that placing the N-pole side (the magnetic
negative energy of the two poles) of a magnet facing any living tissue may attract the
positive electrolytes in that living organism. By placing the N-pole side of a magnet
on the skin, this process is accelerated, and endorses natural healing. The
introduction of the ring magnet with north pole facing the treated surface, at the head
of the plasma needle is expected to improve the plasma uniformity as well as
functioning as healing effect.
1.4 Objective of the Study
The aim of this project is to study, research and redevelop the high frequency
power supply and design a new plasma needle by adding a ring magnet to the plasma
needle to improve the plasma uniformity. This aim will be met through two
objectives:
i. To redevelop a high frequency power supply for plasma needle;
ii. To enhance the design of plasma needle by ring magnet addition.
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1.5 Scope of the Study
The scope of this project is:
i. Develop the high frequency power supply for plasma needle;
ii. Simulation study and modelling on high frequency power supply circuit;
iii. Analysis on the power supply output;
iv. Enhance the design of plasma needle by ring magnet addition.
1.6 Significance of the Study
Although there are various experiments being carried out on the plasma
needle, they did not discuss on the ways of improving the plasma uniformity and
treatment area. This study is to enhance the design of plasma needle by adding a ring
magnet with the purpose of improving the plasma uniformity as well as the healing
effects on the treated are. By improving the plasma uniformity and treatment area,
the treatment time can be shortening and more patients can be benefitted every day.
The findings of this study were important as it opens the ways of improving plasma
uniformity for future research.
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CHAPTER 2
LITERATURE REVIEW
2.1 Introduction
In this chapter, literature review starts with screening the non-thermal plasma
generation, design and applications of plasma needle, which is the big picture of the
research. This research is part of the effort to generate non-thermal plasma for the
usage of plasma needle.
2.2 Plasma Generation
Plasma can be generated from various ways. The most common method in
plasma generation is the electrical breakdown of an electric field in a neutral gas. In
the electric field, the speeded charge carriers will transfer their energy into the
plasma by smashing other atoms and molecules. The electrons will preserve their
major energy in elastic collisions with other particles due to their light weight and
they will only transfer their energy mainly in inelastic collisions. The plasma
generated by the electric fields can be classified into four which are direct current (dc)
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discharges, pulsed dc discharges, radio-frequency discharges and microwave
discharges [6].
The RF discharges can be divided into inductively coupled discharge and
capacitively coupled discharge. Plasma needle is using the capacitively coupled
discharge method to generate plasma in its application. Figure 2.1 shows the general
schematic of an RF capacitively coupled discharge.
Figure 2.1: General Schematic of RF Capacitively Coupled Plasma [7]
2.3 Plasma Needle
In year 2002, Physicist Eva Stoffels and her team had come out with an
innovative idea which is the plasma needle. Plasma needle is a novel design of non-
thermal plasma source which being generated at atmospheric pressure by using the
concept of radio-frequency discharges. It has a single-electrode configuration and
operated with the presence of helium gas [5]. The plasma generated in plasma needle
operates near room temperature and at atmospheric pressure, do not cause pain and
bulk destruction of the tissue yet allows treatment of uneven surface and has a small
penetration depth. These features allow plasma needle to be applied in bio-medical
applications.
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RF plasma at 13.56MHz is generated by using a waveform generator. The
output from waveform generator is amplified by an RF amplifier. The signal is then
directed to a matching network. The power is monitored by using a power meter and
Dual Directional Coupler while the voltage is measured via Tektronics probe. The
electrical measurements show that plasma needle operates at quite low voltages from
200-500 Vpp and the power dissipation range from 10 mW to at most a few watts.
Figure 2.2: Schematic of Plasma Needle Setup [7]
This plasma source will generate the plasma which contains free electrons
and ions, various chemical reactive species and energetic UV photons [8]. UV
emission and density of chemical reactive species are significant in defining the
performance of plasma in the treatment of biological materials. The spore
inactivation with an atmospheric pressure discharge can be mainly due to UV
radiation. With the absence of UV emission, action of chemical reactive species such
as O-, OH
-, N2
+, N2 and He can cause spore inactivation as well. Hence, the spore
inactivation depending on the operating conditions, it can be achieved either under
dominant UV radiation or under purely action of the reactive species [9].
The plasma generation with the presence of helium gas are most stable and
have the widest range of operating conditions. The operating conditions of the
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plasma needle as a function of helium flow rate and percentage of air admixture at a
constant total flow rate are shown in Figure 2.3. This is mainly essential for saving
budgets and convenience of operation in small model openings. Since with the
presence of helium gas, the plasma has very low power dissipation and the sustaining
voltage is tolerable, it is preferable to be used in biomedical applications.
Figure 2.3 Stability Curves of The Plasma: (a) as a function of helium flow rate and
(b) as a function of percentage of air admixture at a constant total flow rate (350 ml
min-1
). Displayed are the breakdown voltages, needed to ignite the plasma (),
minimum operating voltages, just above extinction threshold () and maximum
voltages, just below arcing () [5].
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2.4 Design of Plasma Needle
Plasma needle has relatively simple design. The tungsten needle of 0.3mm is
inserted coaxially in a Perspex tube which has an inner diameter of 4mm [10]. The
tungsten needle serves as the powered electrode here. The Perspex tube is put into
the stainless steel holder and it is protrudes from the stainless steel holder. The length
of the needle normally is around 6-8cm. The electrode is insulated by the Perspex
tube to prevent a discharge along the needle.
The breakdown voltage to generate plasma can easier be achieved with the
presence of gas helium at minimum peak-to-peak RF voltage of around 200V. The
RF signal voltage is connected to plasma needle through a coaxial cable. There is a
gas inlet in the stainless steel holder for gas helium to flow in. Helium is regulated by
a mass flow controller to flow at a rate of 21/min into the Perspex tube [10]. It will
mix with a small amount of air at the tip of the needle. The helium-air mixture is
significant to create active radical species for sterilization [4].
Figure 2.4: Plasma Needle
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The needle should keep as short as possible. This is because the changes in
the power supplied to plasma needle will cause the changes in matching network.
The heating of the needle is thought to be the main reason of the changes. It is better
for coaxial cable that connecting the power supply to the plasma needle to cover
most of the distance rather than lengthen the needle itself. Even though the plasma
kills most of the bacteria, the plasma needle should be sterilized after the treatment
[18]. This is the precaution step taken to avoid any bacteria remain at the needle after
the treatment.
There is heat at the tip of the needle when plasma is formed. The damage will
be done when there is direct contact between the tip of the needle and the skin.
Besides, the tip is very sharp as well. Hence, contact with the skin should be avoided
[18]. The housing covers should cover the needle in total so that the metal tip will
never touch the skin. If there is accident contact made during the treatment, the cover
will touch the skin instead of the warm metal tip.
2.5 Class E Amplifier as RF Plasma Source
Class E amplifier is the improvements and adaptations from typical topology
with the purpose of generating high frequency ac signal. It has higher efficiency
which is around 85% compared to 70% of conventional class B or class C amplifier.
Naturally, class E amplifier has smaller power losses by a factor of 2.3 as compared
to conventional class B and class C amplifier with same transistor at same frequency
and output power [13].
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Figure 2.5: Class E Amplifier Circuit Diagram
The way of generating excitation voltage was based on the modified class E
amplifier where it is different with the original topology. This configuration uses a
metal oxide/semiconductor field-effect transistor (MOSFET), which perform on-off
operation by driving a parallel resonant circuit. The output signal from square wave
generator (CGS3311) will be supplied to a driver, which provides the „on‟ and „off‟
pulses for the MOSFET [15]. The MOSFET output pulses will then be converted
into a sinusoidal high voltage signal by parallel RLC resonant (class E amplifier)
circuit.
In this class E amplifier circuit, the resistive component R or load charge Z is
connected in parallel to the resonant capacitor C. The main modification of this
amplifier compare to the classical amplifier is the resonant capacitor. In this
amplifier, the resonant capacitor works like an ac voltage supply with respect to the
load charge [14]. Consequently, the circuit amplifies the voltage signals that will be
applied to the load.
The amplifier discontinuous conduction mode is determined by the two
possible power switch operating modes. During the ON state (S = ON), the resonant
circuit is only governed by LR and CR, with CT playing the role of a voltage supply.
Thus, the frequency response is
√ (2.1)
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During the OFF state (S = OFF), the resonant circuit is governed by LR, CR
and CT. The current signal I will supply the resonant circuit and the frequency
response is
√ [
] (2.2)
The transistor acts as a switch with a duty ratio D and a work frequency f is
limited by (f1 < f < f2). The S can be expressed by
S = (2.3)
The circuit will show two distinct frequencies according to the state of S. The
capacitive parameter for MOSFET will be fixed according to MOSFET manufacture.
Hence, CT has a fix value which can be found from the datasheet. Thus, the resonant
network parameter LR and CR can be obtained by
*
+ (2.4)
(2.5)
ON wt, for 0 < wt ≤ 2𝜋𝐷
OFF wt, for 2𝜋𝐷 < wt ≤ 2𝜋
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(a)
(b)
Figure 2.6: Experimental waveform of (a) VCR(t), VCT(t), and (b) iLR(t) and IRS(t) [15]
2.6 45MHz MOSFET Driver
Out of many ways of driving MOSFET, IC Drivers offer convenience and
features that attracting many designers. The main advantage of IC Driver is
compactness where it has much smaller sized circuits. Besides, IC Drivers
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intrinsically offer shortest propagation delay hence signals have smaller traverse
distance. It also has shorter rise and fall times. Since all important parameters are
specified in an IC Driver, designers manage to save their time and capital as they
need not go through process of defining, designing and testing circuits to drive the
MOSFET [19].
A proper planning and execution is needed in MOSFETS operation of Class
D or E amplifier and applications that require ultra-fast rise and fall times. The four
important elements are circuit loop inductance, power supply bypassing, circuit
layout, adequate grounding and shielding [19]. The inductive term will be created in
the loop of current path from power supply positive to ground. This loop must be
kept as short as possible by using few tiny capacitors and solder them neatly on the
Vcc and ground pins of Driver IC. Driver IC's bypass capacitor value can be
calculated by:
(2.6)
Where, = quiescent current drawn from Vcc
d = Duty cycle of the PWM waveform
Qg = Total gate charge of the MOSFET
Fsw = Switching frequency
Vripple = Tolerable ripple level on the Vcc
Driver circuit also needs a proper grounding. Loops should be avoided in
driver circuit. Drivers need a very low impedance path for current return to ground.
The three paths of returning current to ground are: 1. between driver IC and the logic
driving it; 2. between the driver IC and its own power supply; 3. between the driver
IC and the source emitter of MOSFET being driven [19]. All these paths should be
kept short in length to reduce inductance and be as wide as possible to reduce
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resistance. A copper plane in a multi-layered PCB can be used to provide a ground
surface under the gate drive circuit. This ground plane should be connected to the
power ground plane of MOSFET source or emitter terminal to avoid different ground
potentials.
With desired rise and fall times in the range of 2 to 3 ns, lengths of current
carrying conductors should be kept as short as possible. Conductor trace‟s partial
inductance can be calculated by:
(
) (2.7)
Where, = inductance in nanohenries
h = height of conductor trace above ground plane
w = width of the conductor trace
It would be better to keep Vcc of Driver to about 20 VDC. If the trace length
from output pin of Driver IC to the gate of MOSFET cannot keep at minimum
distance, the width of the tract should be increased to minimize the loop inductance.
For every tiny increase in conductor length between output pin of Driver IC to the
Gate lead of MOSFET, there will be a major increase in rise time. Besides, it will
cause transmission line effect and resultant RFI/EMI [19]. This inductance could also
resonate with parasitic capacitances of MOSFET, making it hard to acquire clean
current waveforms at rise and fall. Every MOSFET also has some inductance and the
lower this value; the better is the switching performance.
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2.7 MOSFET
MOSFET had been used in most applications of Modern Power Electronics.
In future, we will see more and more applications making use of MOSFET.
MOSFETs can be switched at much higher frequencies with the absence of minority
carrier transport. The limit is imposed by two factors: transit time of electrons across
the drift region and the time required to charge and discharge the input Gate and
„Miller‟ capacitances [20].
Figure 2.7: Symbol and equivalent circuit of a MOSFET
N-Channel MOSFET symbol and an equivalent circuit of MOSFET model
with three inter-junction parasitic capacitances, namely: CGS, CGD and CDS is shown
in Figure 2.7. CGD is referred to the „Miller‟ capacitance and it contributes most to
the switching speed limitation of the MOSFET [20]. Before drain current ID can
begin to flow, CGS needs to be charged to a critical threshold voltage level VGS(th).
Figure 2.8 shows the curve of ID versus VGS for a power MOSFET. It has a slope
which equal to the transconductance, gm. For power MOSFETs, it is
appropriate to consider the relationship to be linear for values of VGS above VGS(th).
The relationship between VGS and ID is parabolic in nature:
[ ] (2.8)
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Figure 2.8: Transfer characteristics of a power MOSFET
2.7.1 MOSFET Turn-on Phenomena
A MOSFET being turned on by a driver in a clamped inductive load is shown
in Figure 2.9. To initiate the conduction from Drain to Source, CGS of MOSFET
needs to be charged to a critical voltage level VGS(th). A current source with a diode D
connected antiparallel across the inductor represent the clamped inductive load [20].
RGint is the MOSFET intrinsic internal Gate resistance. The inter-junction parametric
capacitances (CGS, CGD and CDS) are connected at their own way. VDD is the dc
voltage supply connected to the Drain of the MOSFET through the clamped
inductive load. Rdr is the output source impedance of the Driver. Vcc with the value
of Vp will supply the Driver and its ground is connected to the common ground of
VDD and then returned to the Source of the MOSFET. There will be an amplified
pulse with the amplitude of Vp at the output terminal of the Driver when a positive
going pulse entering the input terminal of the Driver. The output from Driver is fed
to the Gate of the MOSFET through RGext. RGext is the resistance in series with the
Gate of a MOSFET to control the switching speed of the MOSFET [20].
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Figure 2.9: A MOSFET being turned on by a driver in a clamped inductive load
Figure 2.10: A MOSFET being turned off by a driver in a clamped inductive load
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Figure 2.11: MOSFET turn on sequence
MOSFET turn on sequence with variation of different parameters versus time
is shown in Figure 2.11. From t0 to t1, (CGS+CGDl) is exponentially charged until VGS
reaches VGS(th) with a time constant T1. In this time period, Drain voltage remains at
VDD and Drain current, ID has not commenced yet. Between 0 to t1, as VGS rises, IGS
falls exponentially, because it is an RC Circuit. After time t1, as the VGS rises above
VGS(th), MOSFET enters its linear region. At time t1, ID initiates, but the VDS is still
maintain at VDD. However, after t1, ID builds up rapidly. Between t1 to t2, the ID
increases linearly with respect to VGS. At time t2, VGS enters the Miller Plateau level
and VD begins to fall quickly [20].
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From t2 to t4, VGS and IGS remain at the same value. This is called the Miller
Plateau Region. In this time period, most of the drive current from the driver is used
to discharge the CGD and enhance rapid fall of VDS. The ID will only be restricted by
the external impedance in series with VDD. After t4, VGS begins to exponentially rise
again with a time constant T2. During this time interval the MOSFET gets fully
enhanced and the final value of the VGS will determine the effective RDS(on). When
VGS reaches its final value, VDS attains its lowest value, determined by VDS= IDS x
RDS(on) [20].
2.7.2 MOSFET Turn-off Phenomena
Figure 2.10 shows a MOSFET being turned off by a driver in a clamped
inductive load. The turn-off phenomenon is shown in Figure 2.12. There are two
different decay rates when the output from the Driver drops to zero for turning off
MOSFET. From time 0 to t1, VGS initially decays exponentially at the rate of time
constant T2 but it decays exponentially at the rate of time constant T1 when beyond
T4. The first delay here is required to discharge the CISS capacitance from its initial
value to the Miller Plateau level [20]. From t0 to t1, the gate current is flowing
through CGS and CGD capacitances of MOSFET. During this time interval, ID remains
constant but VDS begins to rise. From t1 to t2, VDS rises from VDS(on) towards its final
off state value of VDS(off) .
From t3 to t4, the VGS begins to fall further below VGS(th). CGS will be
discharge through any external impedance between Gate and Source terminals. The
MOSFET is in its linear region and ID drops rapidly towards zero value. At the
beginning of this interval, the VDS was at its off state value VDS(off) and the MOSFET
will completely turned off at t4 [20].
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Figure 2.12: MOSFET turn off sequence
2.8 Magnetic Effects on Living Organism
It is proven that magnetic fields do affect the human body in different ways,
and these may be best to be used in therapy [14]. When injury occur, that particular
area is magnetically positive (south pole) and it will become magnetically negative
after few hours (healing occur). North pole magnets have the ability to end the
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enlargement of growth and contamination while south pole magnets able to arouse
growth of tissue and living systems (bacteria). Hundreds of experiments show that
north pole, the magnetic negative energy has decelerated, controlled and stopped
further development of active cancer site [15]. Due to its characteristic, north pole is
preferred as it has healing effects, relieves pains, reduce inflammations as well as the
infections.
2.9 Applications of Plasma Needle
2.9.1 Dental Applications
Major problem in dentistry are dental cavities. At the moment, laser
technique or traditional method, mechanical drilling can be used to clean the cavities
in teeth. The cleaning process is purely depends on the skill of the dentist. During the
cleaning process, patient might be suffering as both methods involve heating or
vibrations. Heating and vibrations can aggravate the nerve and it can be very painful
to the patient.
Plasma can prevent patient from suffering as it can sterilize the dental cavities
without going through drilling and heating process. This is because the active plasma
species it produces can easily access small irregular cavity and gap. The excess
active species will recombine among themselves or reacting with ambient air and
water molecules once the treatment is completed. Besides, plasma does not cause
major heating to dental pulp yet able to kill the bacteria [10]. Furthermore, cost of
plasma is relatively inexpensive.
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2.9.2 Plasma Treatment of Mammalian Vascular Cells
Plasma treatment also offers possibility in aiding wound healing. Experiment
between plasma needle and cultured cells were carried out to test for the effects of
electrical properties on cell detachment and necrosis. Mammalian cells that placed
under plasma have the 10s of treatment time for detachment. For short exposure
under plasma yet has the good effect, the layer needed to be thin which is less than
1mm [11]. This has opened the space for cold plasma to be used in healing the
wound.
2.9.3 Cancer Treatment
Nowadays, the only treatment for cancer is either chemotherapy or surgery.
Chemotherapy works against cancer by damaging the nucleus of the cells in the body
that are undergoing the process of division. The cancer-fighting drugs are injected
directly into the body and it will travel around the body to damage and kill the cancer
cells where it has spread. However, it has the side effect of stopping the hair follicles
and skin from dividing.
Plasma treatment can prevent patients from suffering as it does not have the
side effects. Plasma treatment has high-precision on the cells as there will be sharp
boundary line between non-plasma treated region and plasma-treated regions [12].
The high-precision of plasma treatment allows it to be applied directly to the cancer
cells without damaging the surrounding normal cells especially in biomedical
application.
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CHAPTER 3
RESEARCH METHODOLOGY
3.1 Introduction
This chapter will discuss the methodology used to complete the design of
plasma needle and high frequency power supply for bio-medical applications. Sub
title included in this chapter is methodology procedure, related guidelines and
datasheet, and software used for modelling. Methodology procedure will list out all
necessary steps to finish the design in a simple flow chart. Guidelines and datasheets
that related to the design will be study as well. Software used in this study are
SolidWorks 2011 and Multisim 10.0.
In this study, a novel design of plasma needle will be designed by using
SolidWorks 2011. A ring magnet will be added to the head of the plasma needle and
it is expected to increase the plasma uniformity as well as the healing effect on the
treated area. Multisim 10.0 will be used for power supply circuit simulation. The
circuit will be simulated in Multisim 10.0 before proceed to hardware development
in breadboard and followed by printed circuit board.
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3.2 Methodology Procedure
The methodology of the design of plasma needle and high frequency power
supply is as summarized in the flow chart below:
Literature Review
Designing and simulation of
Class E amplifier
Designing a plasma needle with
a ring magnet
Hardware development of
plasma needle
Campare the hardware result with the
simulation result
Draw conclusion and
report preparation
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3.3 Related Guidelines and Datasheets
In order to design the plasma needle and high frequency power supply, the
related journal papers were read and used as references and guidelines. The
specifications of designed plasma needle will be based on the current plasma needle
designed by Eva Stoffels and her team. Same thing goes to the high frequency power
supply as well. The power supply circuit will be modified base on the current circuit.
Besides, related datasheets will be read so that the best components will be chosen in
the circuit. It is very important to choose the correct values and ratings for the
components used in the designed circuit.
3.4 Software Used for Modelling
In this study, SolidWorks 2011 will be used to design the plasma needle
while Multisim 10.0 will be used for class E power amplifier circuit simulation.
3.4.1 SolidWorks 2011
SolidWorks 2011 was chosen as the software to design the plasma needle. It
is a 3D software tools which is more user friendly and easier to learn. It has variety
of user interface tools and capabilities to help designers in creating and editing
models well. Those tools are windows functions, SolidWorks document windows
and function selection and feedback.
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SolidWorks patent-pending rapid dimensions show the new dimension
placement options and neatly re-arrange current dimensions for selection. The
configuration publisher lets users easily publish a model configurator interface to a
web-based marketplace for 3D parts, assemblies, and other content for selection of
model options. Besides, SolidWorks 2011 also offers improved reference plane
creation methods, sheet metal functionality, weldment performance, component
imaging capabilities, and direct editing tools.
SolidWorks Simulation Premium arms the users with tools to easily validate
design decisions, uncover hidden problems before they affect production and hence
save a lot of money in prototyping. New version also has the event-based motion
simulation, proximity sensors and automatic edge-weld sizing. The overhauled
simulation advisor will guide learners through their first few successful simulations,
shortening the learning curve and adding a layer of protection against errors.
SolidWorks Sustainability software also makes the sustainable design reliable,
reachable and simple. It helps users to govern the carbon footprint, energy
consumption, and air/water impacts in a product design‟s raw material sourcing,
manufacture, use, and disposal. The users also can compare multiple designs at the
same time due to the configuration support in this software. The assembly
visualization tool color-codes parts are based on their total environmental impact.
SolidWorks 2011 was designed to be quicker and more proficiently,
optimized the support for manufacturing and upgraded the collaboration and
visualization. It allows users to stay longer in this software without reboot the
application. On the other hand, sustainability data also can be added to the assembly
visualization tool. In short, SolidWorks 2011 provides more than 200 enhancements
to be more user-friendly so that they will have more expressive experience and
results throughout the entire process.
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3.4.2 Multisim 10.0
Multisim is an SPICE simulation program used in industry and classroom
teaching. It is the basis of the NI circuits to train a professional circuit designer
through practical application in designing, modelling, and testing of electrical
circuits. Besides, it is also designed for schematic entry, simulation, and finally leads
to implementation and production of PCB layout.
Multisim provides the reliable circuit design for expertise. It keeps improving
to ensure the circuit designers and researchers can move faster to the stage of PCB
production. One of the advantages of circuit design by using this software is the
designers will have the accurate part selection. Multisim has the database of more
than 22,000 components from top semiconductor manufacturers such as Analog
Devices, National Semiconductor, NXP, ON Semiconductor, and Texas Instruments.
Secondly, it can verify the designs by the simulation. The simulation result
can be used for analysis purpose. Multisim has around 20 industry standard SPICE
analyser and 22 measurement instruments for the designer to validate the
performance of the designed circuit. Thirdly, the design circuit can be translated
faster to PCB prototype since the NI Ultiboard layout environment is wholly
integrated with Multisim. It can save the transfer time and ease the designer work.
Lastly, the design prototype also can be validated by LabVIEW which
integrated together with NI Multisim. The relation between real and simulated results
performance can be verified by integrating the Multisim measurements into NI
LabVIEW. This is important to ensure the physical prototype meets the
specifications. Multisim was chosen as simulation software due to the advantages
stated above and more importantly it is free and easy to learn.
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CHAPTER 4
PLASMA NEEDLE DESIGN
4.1 Introduction
This section will discuss the design of plasma needle. It will discuss about the
components used, the dimension and the description of the model. The plasma needle
will be designed by using SolidWorks 2011 software.
4.2 Modelling Components
Plasma needle has a very simple design. It comprised of a tungsten needle,
ceramic rod, Pyrex tube, cylinder shape plastic, plastic holder, BNC female, washer
and ring magnet. Figure 4.1 shows the components of the designed plasma needle.
The holder is made of plastic so that it will has a lighter weight and be more user-
friendly.
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Figure 4.1: Components of Plasma Needle
4.3 Modelling Dimensions
Figure 4.2: Dimensions of Plasma Needle
Cylinder Shape
Pyrex Tube
Washer
Tungsten Needle
Ceramic Rod
BNC Female
Ring Magnet
Plastic Holder
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The designed plasma needle has the length of 118mm with the width of
18mm. it is kept as short and thin as possible so that it is easier for handling. The
plastic holder in the design has the length of 50mm and width of 20mm. One end of
the plastic holder is connected to the BNC female while another end is connected to
the Perspex tube. The gas inlet in the plastic holder has the slope of 450. It is
designed with the slope of 450
so that the gas inlet pipe does not obstruct the
treatment process when plasma needle is being applied in dentistry or other
applications.
Besides, there is a 2mm thick Perspex between the washer and the ring
magnet. The 2mm Perspex is used to fixed the ring magnet at its position. The ring
magnet has the outer diameter (OD) of 18mm and internal diameter (ID) of 12mm.
This ring magnet has to be custom-made as the size is too small and rarely found in
the magnet manufacturing plant.
4.4 Modelling Descriptions
The designed plasma needle has a very simple design. It comprised of a
tungsten needle, ceramic rod, Pyrex tube, cylinder shape plastic, plastic holder, BNC
female, washer and ring magnet. The needle consisted of a tungsten needle (electrode)
of 0.5mm in diameter which is encapsulated in a ceramic rod. The ceramic rod is
used to provide mechanical support as well as electrical insulation for the electrode.
There is also a cylinder shape plastic with holes in the middle of the plasma needle to
provide extra mechanical support to the tungsten and ceramic. The hole in the middle
of cylinder shape plastic is to put the power electrode while the other holes are for
gas helium to go through.
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Figure 4.3: Plasma Needle Model
The tip of tungsten needle is uncovered 2mm so that the tungsten can mix
with helium to create the plasma. Both electrode and ceramic tube are embedded in
the Pyrex tube. The Pyrex tube is used to insulate the needle to prevent a discharge
along the pin. The tube is protrudes from the plastic holder. The plastic holder is
designed with a gas inlet hence the gas helium can flow in from the gas inlet.
Another end of the plastic holder is threaded inside so that it can grip the BNC
female tightly. BNC will be connected to the power supply via the coaxial cable.
The novel design is made by adding a 10mm ring magnet at the tip of the
plasma needle. A washer is added so that the ring magnet can be attracted to it. The
ring magnet with different magnetic field strength (Tesla) will be tested to find for
the best magnetic field strength in creating the uniform plasma besides having the
healing effect on the treated area. The washer will only be used in the experiment
stage where it can be removed after the best magnetic field strength was found. The
ring magnet can be glued directly to the Perspex tube after confirm the magnetic
field strength of the ring magnet.
RF Signal Ring Magnet
Gas Inlet
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Figure 4.4: The Pyrex tube moved 5mm into the plastic holder
The Perspex tube which protrudes from the plastic holder can move 5mm into
the plastic holder as shown in Figure 4.4. This is specially design for sterilizing
purpose. Even though the plasma kills most of the bacteria, the plasma needle needs
to be be sterilized after the treatment. Figure 4.5 shows the designed plasma needle
after rendered by using SolidWorks 2011.
Figure 4.5: Plasma Needle after Rendered
Ring Magnet
Needle Tip
Gas Inlet
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CHAPTER 5
HIGH FREQUENCY POWER SUPPLY
5.1 Introduction
This section discusses the design of high frequency power supply for bio-
medical applications. This research aims to design a high frequency power supply
which can generate a voltage up to 200V with the frequency of 13.56MHz. The
design was started with the software simulation and followed by hardware
development. The simulation and hardware development will be discussed in detail.
5.2 Simulation Development
The design of high frequency power supply was started with software
simulation. This is the step to verify whether the design circuit is functioning well
before continue with hardware development. In this research, Multisim 10.0 was
used as the simulation software.
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5.2.1 Simulation of Modified Class E Amplifier
Figure 5.1: Modified Class E Amplifier Simulation Circuit
Figure 5.1 shows the modified Class E amplifier simulation circuit. This
circuit is very simple yet able to generate high voltage and high frequency in
generating non-thermal plasma. The component L1 is functioning as a choke
inductor for filtering. It allows only DC signal to pass through. The RLC load
consisted of R1, L3 and C2. L2 and C1 were combined to form the resonant circuit
with the frequency of 13.56MHz. Their value can be adjusted based on the input
frequency by using the formula
√ (5.1)
The voltage range from 200Vpp to 600Vpp is needed in generating non-
thermal plasma. The voltage is inversely proportional to the required helium flow
rate. The higher the voltage the lower the gas helium required to generate the plasma.
When the gas helium is lower, the cost of generating the plasma is lowered down as
well.
VCT VCR VO
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According to datasheet RF MOSFET DE275X2-102N06A, it has the VGS(th)
range from 2.5V to 5.5V. Hence, the 5Vp square wave input signal was used to drive
the MOSFET in the simulation. The 5Vp square wave signal was directly enter into
MOSFET without go through a driver. However, there will be a MOSFET driver,
DEIC515 in the real circuit to drive the MOSFET.
In the simulation circuit, the function generator with 5Vp square wave was
used to replace the MAX038. MAX038 is the signal generator IC which able to
generate the waveform frequency up to 20MHz. The input voltage of 20V was used
in the modified Class E amplifier simulation circuit. The 20V input voltage was
connected to the 33µH choke inductor.
The Simulated Tektronix Oscilloscope was used in the simulation software to
visualize the output from the circuit. Since the Simulated Tektronix Oscilloscope has
four probes, it can have four outputs at the same time. In this simulation, only two
output signals were shown at the same time.
5.3 Hardware Development
Hardware development was conducted after the software simulation and
components selection. It was started with frequency waveform generator, MAX038,
followed by Driver DEIC 515 and MOSFET DE275X2-106N06A.
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5.3.1 MAX038 Frequency Waveform Generator
Figure 5.2: MAX038 Frequency Waveform Generator Circuit
Figure 5.2 shows the MAX038 waveform generator circuit. MAX038 can
generate square wave, sine wave and triangle wave. The input to A0 ( pin 3 ) and A1
( pin 4 ) will determine type of waveforms being generated. The MOSFET needs
square wave for its input signal. Hence, both inputs to A0 and A1 were set to 0 to
have the square wave output signal. CF was fixed at 33pF and the frequency of the
output waveform can be adjusted by varying the 20kΩ potentiometer, RIN.
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Figure 5.3: MAX038 Hardware Circuit
The +5V was connected to pin 17 while -5V was connected to pin 20 of
MAX038. The ±5V was supplied from the regulated DC power supply. The 4.7µH
capacitors were used to reduce noise and stabilize the input voltage to MAX038. The
output from MAX038 will be connected to the input of MOSFET Driver, DEIC515.
5.3.2 DEIC515 MOSFET Driver Circuit
Figure 5.4: DEIC515 MOSFET Driver Circuit
RIN, 20kΩ
MAX038
4.7µ
F
12kΩ
1nF Output
-5V
+5V
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DEIC515 is a 15A low side ultrafast RF MOSFET driver. It can drive the
MOSFET with the frequency up to 45MHz. However, a very large transient will be
created in DEIC515 due to the high currents and high speeds. L1 as shown in Figure
5.4 is the simple tri-filar winding on a small ferrite core. It is the common mode
choke used at the DEIC515 input to avoid false triggering by directing the input
signals to follow the internal die potential changes.
The input and ground of the square wave were connected to the common
mode choke before entering IN and INGND of the DEIC515. The input voltage, VCC
for DEIC515 was 15V. The input square wave signal has the amplitude of 5Vp. The
output from DEIC 515 was connected to MOSFET DE275X2-102N06A input.
Figure 5.5: DEIC515 Hardware Circuit
5.3.3 DEIC515 and DE275X2-102N06A MOSFET Circuit
Figure 5.6 shows the Driver DEIC515 and MOSFET DE275X2-102N06A
circuit on breadboard. The driver DEIC515 was used to drive the MOSFET at
frequency of 5MHz and 8MHz. The output from DEIC515 was connected to the
Gate of the MOSFET. The input voltage, VDD was set at 15V and connected to the
Output 10µF
10µF VCC
DEIC515
INVCC
INGND
IN
Ground
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Drain of the MOSFET. The output from MOSFET was attached to the Class E
amplifier circuit.
Figure 5.6: DEIC515 and MOSFET Hardware Circuit
DEIC515
DE275X2-102N06A
Output
VDD Ground
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42
CHAPTER 6
RESULTS AND DISCUSSIONS
6.1 Introduction
This section discusses the simulation and the experimental results in this
research. It will start with the simulation result of modified Class E amplifier and
follow by the MAX038, DEIC515 and DE275X2-102N06A hardware results. The
output from the MOSFET, DE275X2-102N06A will be combined with the class E
amplifier to get the high voltage and high frequency output. The results obtained
from the experiment will be compared with the simulation results.
6.2 Simulation Results For Modified Class E Amplifier
Figure 6.1 and 6.2 show the simulated waveforms of VCT, VCR, Vo and Vin.
The simulated results as shown in Figure 6.1 and 6.2 prove that the modified Class E
amplifier able to generate an output voltage of 505Vpp at the frequency of
13.56MHz with an input voltage of 20V. The output voltage is high enough to
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43
generate non-thermal plasma after mix with the helium gas. VCT is the simulated
waveform that obtained from the Drain of the MOSFET. It was amplified from 15V
to 99.6Vpp.
Figure 6.1: Simulated waveform of VCT and VCR
Figure 6.2: Simulated waveform of Vin and Vo
All the components are assumed ideal in the simulation. In reality, many
factors will affect the output of the circuit. The output voltage will be lower than the
simulation result in real experiment.
VCT
VCR
Vo
Vin
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6.3 Hardware Results
The results of MAX038 frequency waveform generator, DEIC515 MOSFET
Driver as well as DE275X2-102N06A MOSFET will be shown in this section.
6.3.1 MAX038 Frequency Waveform Generator
Figure 6.3(a), (b) and (c) show the output signals from MAX038 at frequency
of 5MHz, 10MHz and 13.75MHz. The frequency was varied by adjusting the 20kΩ
potentiometer. The results show that MAX038 can generate square wave at high
frequency. It can be used as the signal generator to replace the function generator in
generating input signal for MOSFET. This will definitely reduce the cost of the power
supply since MAX038 is cheaper than a function generator.
(a)
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45
(b)
(c)
Figure 6.3: Output of MAX038 at (a) 5MHz, (b) 10MHz and (c) 13.75MHz
6.3.2 DEIC515 MOSFET Driver
Figure 6.4(a), (b) and (c) show the DEIC515 MOSFET Driver output signal at
frequency of 1MHz, 5MHz and 10MHz. It can be observed that the output from the
Driver has the amplitude of 14Vpp at the frequency of 1MHz. At frequency of 5MHz,
the amplitude was reduced to 7Vpp. The amplitude was decreased to 3.5Vpp at
frequency of 10MHz. However, the square shape still can be observed although the
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frequency increased to 10MHz. This results show that Driver DEIC515 has the ability
to drive the signal at high frequency.
(a)
(b)
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(c)
Figure 6.4: Output of DEIC515 at (a) 1MHz, (b) 5MHz and (c) 10MHz
The problem faced was the signal output voltages were decreasing when the
frequency increased. The voltage at the voltage generator also decreased when the
frequency of the input signal increased. There were voltage drop along the circuit
when high frequency being applied to the Driver. The circuit path was inductive and
the reactance, XL= jwL. When f=13.56MHz, the reactance was very large. At this
time, it is believed that most of the supply voltage did not pass through the Driver but
go through the capacitor that connected between the VCC and the ground.
6.3.3 DEIC515 and DE275X2-102N06A MOSFET
Figure 6.5 shows the output signals of MOSFET DE275X2-102N06A being
drove by DEIC515. The output signal from MOSFET has the output voltage of
2.53Vpp at frequency of 5MHz. At frequency of 8MHz, the signal has output voltage
of 1.25Vpp.
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(a)
(b)
Figure 6.5: Output of DE275X2-102N06A at (a) 5MHz and (b) 8MHz
From the results, it can be observed that the voltage decrease when the
frequency was being increased. It is believed that the MOSFET is not ON during the
experiment since no amplification occurred. The voltage drop along the circuit paths
need to be tackled in order to solve this problem.
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CHAPTER 7
CONCLUSION & RECOMMENDATION
7.1 Introduction
In this chapter, the researcher will restate the objectives and make the
conclusion based on the results. Besides, recommendation for future research also
will be indicated.
7.2 Conclusion
This research had presented the design of plasma needle and high frequency
power supply for bio-medical applications. First objective of the research to design a
plasma needle was achieved successfully. SolidWorks 2011 software was used to
design the plasma needle. The modelling components, dimensions and descriptions
were discussed in chapter 4 previously. The newly design plasma needle is expected
to improve the plasma uniformity as well as the healing effects on the treated area. It
will be lighter and easier for handling with diverse design and material used.
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The second objective of the research to design the high frequency power
supply was partially achieved. The simulation of the power supply circuit was
simulated successfully where it managed to produce the high voltage at high
frequency. When it comes to the hardware development, the output at both Driver
and MOSFET were not similar to the simulation result. The DEIC515 and
DE275X2-102N06A were able to drive the input signal at high frequency. However,
the voltage dropping at high frequency needs to be settled before proceed to the
amplifier circuit stage.
Current method of high frequency power supply is very expensive since it
consisted of commercialize function generator and research amplifier. These
equipments are specially used in laboratory for researching and studying purpose.
The research and improvement on the high frequency power supply must be carried
on in order to develop a cheaper yet simpler power supply for future bio-medical
applications.
7.3 Recommendation
Based on the research of this study, here are several recommendations for
future work to improve the high frequency power supply as well as the plasma
needle in bio-medical applications:
1. MAX038 is able to generate the output waveform at high frequency. It can be
used to replace the function generator in the power supply circuit. However,
MAX038 is no longer manufactured by MAXIM and it is hard to buy a large
amount of MAX038 in the market. Due to this reason, an alternative for
MAX038 should be found.
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51
2. For RF design, the high speed switching and losses always become the problem
in circuit design. Using DEIC515 and MOSFET DE275X2-102N06A in the
designed circuit was the right one. It has an excellent thermal transfer and able to
optimize the switching speed of the output waveform. Hence, the RF Driver and
RF MOSFET should be used in the future research.
3. During the hardware development, the RF components should be soldered
directly on the PCB instead of testing on the breadboard. The circuit paths also
must be kept as short as possible. These ways are taken to reduce the noises and
power losses during the high speed switching.
4. The introduction of ring magnet is expected to improve the plasma uniformity as
well as the healing effect at the treated area. Therefore, the designed plasma
needle should be fabricated in order to investigate its effects. The most suitable
magnetic field strength can be determined after the experiment.
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REFERENCES
1. M K Boudam, M. M., B Saoudi, C Popovici, N Gherardi and F Massines
(2006). Bacterial Spore Inactivation by Atmospheric-Pressure Plasma In The
Presence or Absence of UV Photons as Obtained with the Same Gas Mixture.
2. Kieft, I. E., M. Kurdi, et al. (2006). Reattachment and Apoptosis After
Plasma-Needle Treatment of Cultured Cells. Plasma Science, IEEE
Transactions on 34(4): 1331-1336.
3. Roxana Silvia Tipa, G. M. W. K. (2011). Plasma-Stimulated Wound Healing.
IEEE Transactions On Plasma Science 39(11): 2978-2979.
4. Laroussi, M. (2009). Low-Temperature Plasmas for Medicine? Plasma
Science, IEEE Transactions on 37(6): 714-725.
5. E Stoffels, A. J. F., W W Stoffels and G M W Kroesen (2002). Plasma needle:
a non-destructive atmospheric plasma source for fine surface treatment of
(bio)materials. Plasma Sources Science And Technology 11: 383-388.
6. H Conrads, M. S. (2000) Plasma generation and plasma sources. 9, 441-454
7. I.E.Kieft (2005). Plasma Needle: exploring biomedical applications of non-
thermal plasmas, Printservice Technische Universiteit Eindhoven: 153.
8. Moisan, M., J. Barbeau, et al. (2001). Low-temperature sterilization using gas
plasmas: a review of the experiments and an analysis of the inactivation
mechanisms. International Journal of Pharmaceutics 226(1–2): 1-21.
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53
9. M K Boudam, M. M., B Saoudi, C Popovici, N Gherardi and F Massines
(2006). Bacterial spore inactivation by atmospheric-pressure plasma in the
presence or absence of UV photons as obtained with the same gas mixture.
10. Sladek, R. E. J., E. Stoffels, et al. (2004). Plasma Treatment of Dental
Cavities: A Feasibility Study. Plasma Science, IEEE Transactions on 32(4):
1540-1543.
11. Ingrid E. Kieft, D. D., Anton J.M. Roks and Eva Stoffels (2005). Plasma
Treatment of Mammalian Vascular Cells: A Quantitative Description. IEEE
Transactions on Plasma Science 33(2): 771-775.
12. D. Kim, B. G., D.B. Kim, W. Choe and J.H. Shin (2009). A Feasibility Study
for the Cancer Therapy Using Cold Plasma. ICBME: 355-357.
13. Sokal, N. O. (Jan/Feb 2001) Class-E RF Power Amplifiers. QEX: 9-20.
14. Rosendo Peña-Eguiluz, M., IEEE, José Arturo Pérez-Martínez, Régulo
López-Callejas, and J. S.-P. Antonio Mercado-Cabrera, Blanca Aguilar-
Uscanga, Arturo E. Muñoz-Castro, Raúl Valencia-Alvarado, Samuel R.
Barocio-Delgado, Benjamín G. Rodríguez-Méndez, and Aníbal de la Piedad-
Beneitez (2010). Analysis and Application of a Parallel E-Class Amplifier as
RF Plasma Source. IEEE Transactions on Plasma Science 38(10).
15. Jose A. Perez-Martinex, R. P.-E., Regulo Lopez-Callejas, Antonio Mercado-
Cabrera, Raul Valencia Alvarado, Samuel R. Barocio, Anibal de la Piedad-
Beneitez (2008). Power Supply for Plasma Torches Based on a Class-E
Amplifier Configuration.
16. Sadafi, H. A. (1998). The Therapeutic Applications of Pulsed and Static
Magnetic Fields. 2nd International Conference on Bioelectromagnetism.
Melbourne, Australia.
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54
17. Albert Roy Davis and Walter C. Rawls, J. (1988). The Magnetic Effect and
Magnetism and Its Effects on the Living System, Exposition Press.
18. Ven, G. v. d. (2006). BEP: Design of a guiding mechanism for the plasma
needle”, Technische Universiteit Eindhoven.
19. Abhijit D. Pathak, S. O. (2003). Unique MOSFET/IGBT Drivers and Their
Applications in Future Power Electronics Systems. Power Electronics and
Drive Systems, PEDS 2003. 1: 85-88.
20. Abhijit D. Pathak (2001). MOSFET/IGBT Drivers, Theory and Applications,
IXYS Corporation.
21. Zirnheld, J. L., S. N. Zucker, et al. (2010). Nonthermal Plasma Needle:
Development and Targeting of Melanoma Cells. Plasma Science, IEEE
Transactions on 38(4): 948-952.
22. Lo Keat How (2011). Modeling And Design of Plasma Needle Supply. IVAT.
Johor, Universiti Teknologi Malaysia. Bachelor of Engineering (Electrical).
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APPENDIX A
Apparatus for Hardware Experiment
Regulated DC Power Supply, PSM 2/5A
Function Generator, Tektronix AFG 3021B
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Oscilloscope, LeCray LT344L
Fluke Multimeter
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APPENDIX B
Datasheet
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________________General DescriptionThe MAX038 is a high-frequency, precision functiongenerator producing accurate, high-frequency triangle, sawtooth, sine, square, and pulse waveforms with aminimum of external components. The output frequencycan be controlled over a frequency range of 0.1Hz to20MHz by an internal 2.5V bandgap voltage reference and an external resistor and capacitor. Theduty cycle can be varied over a wide range by applyinga ±2.3V control signal, facilitating pulse-width modula-tion and the generation of sawtooth waveforms.Frequency modulation and frequency sweeping areachieved in the same way. The duty cycle and frequency controls are independent.
Sine, square, or triangle waveforms can be selected atthe output by setting the appropriate code at two TTL-compatible select pins. The output signal for allwaveforms is a 2VP-P signal that is symmetrical aroundground. The low-impedance output can drive up to ±20mA.
The TTL-compatible SYNC output from the internaloscillator maintains a 50% duty cycle—regardless ofthe duty cycle of the other waveforms—to synchronizeother devices in the system. The internal oscillator canbe synchronized to an external TTL clock connected to PDI.
________________________ApplicationsPrecision Function Generators
Voltage-Controlled Oscillators
Frequency Modulators
Pulse-Width Modulators
Phase-Locked Loops
Frequency Synthesizer
FSK Generator—Sine and Square Waves
____________________________Features♦ 0.1Hz to 20MHz Operating Frequency Range
♦ Triangle, Sawtooth, Sine, Square, and PulseWaveforms
♦ Independent Frequency and Duty-CycleAdjustments
♦ 350 to 1 Frequency Sweep Range
♦ 15% to 85% Variable Duty Cycle
♦ Low-Impedance Output Buffer: 0.1Ω
♦ Low 200ppm/°C Temperature Drift
_______________Ordering Information
MA
X0
38
High-Frequency Waveform Generator
________________________________________________________________ Maxim Integrated Products 1
20
19
18
17
16
15
14
13
12
11
1
2
3
4
5
6
7
8
9
10
V-
OUT
GND
V+A1
A0
GND
REF
TOP VIEW
MAX038
DV+
DGND
SYNC
PDIFADJ
DADJ
GND
COSC
PDO
GNDIIN
GND
DIP/SO
___________________ Pin Configuration
19-0266; Rev 5; 2/04
EVALUATION KIT
AVAILABLE
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
PART TEMP RANGE PIN-PACKAGE
MAX038CPP 0°C to +70°C 20 Plastic DIP
MAX038CWP 0°C to +70°C 20 SO
MAX038C/D 0°C to +70°C DiceMAX038EPP* -40°C to +85°C 20 Plastic DIPMAX038EWP* -40°C to +85°C 20 SO
*Contact factory prior to design.
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MA
X0
38
High-Frequency Waveform Generator
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(Circuit of Figure 1, GND = DGND = 0V, V+ = DV+ = 5V, V- = -5V, VDADJ = VFADJ = VPDI = VPDO = 0V, CF = 100pF,RIN = 25kΩ, RL = 1kΩ, CL = 20pF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functionaloperation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure toabsolute maximum rating conditions for extended periods may affect device reliability.
PARAMETER SYMBOL MIN TYP MAX UNITS
Frequency TemperatureCoefficient
∆Fo/°C
200ppm/°C
600
IIN Offset Voltage VIN ±1.0 ±2.0 mV
Frequency ProgrammingCurrent
IIN1.25 375
µA
(∆Fo/Fo)∆V+
±0.4 ±2.00Frequency Power-SupplyRejection (∆Fo/Fo)
∆V-±0.2 ±1.00
%/V
Output Peak-to-Peak Symmetry VOUT ±4 mV
Maximum Operating Frequency Fo 20.0 40.0 MHz
2.50 750
Output Resistance ROUT 0.1 0.2 ΩOutput Short-Circuit Current IOUT 40 mA
Amplitude VOUT 1.9 2.0 2.1 VP-P
Rise Time tR 12 ns
Fall Time tF 12 ns
Duty Cycle dc 47 50 53 %
Amplitude VOUT 1.9 2.0 2.1 VP-P
Nonlinearity 0.5 %
Duty Cycle dc 47 50 53 %
CONDITIONS
VFADJ = -3V
VFADJ = 0V
VFADJ = -3V
V- = -5V, V+ = 4.75V to 5.25V
V+ = 5V, V- = -4.75V to -5.25V
Short circuit to GND
10% to 90%
90% to 10%
VDADJ = 0V, dc = tON/t x 100%
CF ≤ 15pF, IIN = 500µA
VFADJ = 0V
FO = 100kHz, 5% to 95%
VDADJ = 0V (Note 1)
V+ to GND................................................................-0.3V to +6VDV+ to DGND...........................................................-0.3V to +6VV- to GND .................................................................+0.3V to -6VPin Voltages
IIN, FADJ, DADJ, PDO .....................(V- - 0.3V) to (V+ + 0.3V)COSC .....................................................................+0.3V to V-A0, A1, PDI, SYNC, REF.........................................-0.3V to V+GND to DGND ................................................................±0.3V
Maximum Current into Any Pin .........................................±50mAOUT, REF Short-Circuit Duration to GND, V+, V- ...................30s
Continuous Power Dissipation (TA = +70°C)Plastic DIP (derate 11.11mW/°C above +70°C) ..........889mWSO (derate 10.00mW/°C above +70°C).......................800mWCERDIP (derate 11.11mW/°C above +70°C)...............889mW
Operating Temperature RangesMAX038C_ _ .......................................................0°C to +70°CMAX038E_ _ ....................................................-40°C to +85°C
Maximum Junction Temperature .....................................+150°CStorage Temperature Range .............................-65°C to +150°CLead Temperature (soldering, 10s) .................................+300°C
Amplitude VOUT 1.9 2.0 2.1 VP-P
CF = 1000pF, FO = 100kHzTHD %
Fo/°C
FREQUENCY CHARACTERISTICS
OUTPUT AMPLIFIER (applies to all waveforms)
SQUARE-WAVE OUTPUT (RL = 100Ω)
TRIANGLE-WAVE OUTPUT (RL = 100Ω)
SINE-WAVE OUTPUT (RL = 100Ω)
Total Harmonic Distortion 2.0
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MA
X0
38
High-Frequency Waveform Generator
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)(Circuit of Figure 1, GND = DGND = 0V, V+ = DV+ = 5V, V- = -5V, VDADJ = VFADJ = VPDI = VPDO = 0V, CF = 100pF,RIN = 25kΩ, RL = 1kΩ, CL = 20pF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
Note 1: Guaranteed by duty-cycle test on square wave.Note 2: VREF is independent of V-.
PARAMETER
DADJ Nonlinearity
SYMBOL MIN TYP MAX
dc/VFADJ 2 4
UNITS
%
Duty Cycle dcSYNC 50 %Fall Time tF 10 nsRise Time tR 10 ns
Change in Output Frequencywith DADJ
DADJ Input Current IDADJ 190 250 320 µADADJ Voltage Range VDADJ ±2.3 V
Fo/VDADJ ±2.5 ±8 %
Duty-Cycle Adjustment Range dc 15 85 %
Maximum DADJ ModulatingFrequency
FDC 2 MHz
Output Low Voltage
FADJ Input Current IFADJ 190 250 320 µAFADJ Voltage Range VFADJ ±2.4 VFrequency Sweep Range
VOL 0.3 0.4 V
Fo ±70 %FM Nonlinearity with FADJ
Output High Voltage
Fo/VFADJ ±0.2 %
VOH 2.8 3.5 V
Change in Duty Cycle with FADJ dc/VFADJ ±2 %
Output Voltage VREF 2.48 2.50 2.52 V
CONDITIONS
-2V ≤ VDADJ ≤ +2V
90% to 10%, RL = 3kΩ, CL = 15pF10% to 90%, RL = 3kΩ, CL = 15pF
-2V ≤ VDADJ ≤ +2V
-2.3V ≤ VDADJ ≤ +2.3V
ISINK = 3.2mA
-2.4V ≤ VFADJ ≤ +2.4V-2V ≤ VFADJ ≤ +2V
ISOURCE = 400µA
-2V ≤ VFADJ ≤ +2V
IREF = 0
Temperature Coefficient VREF/°C 20 ppm/°C0mA ≤ IREF ≤ 4mA (source) 1 2
Load Regulation VREF/IREF -100µA ≤ IREF ≤ 0µA (sink) 1 4mV/mA
Line Regulation VREF/V+ 4.75V ≤ V+ ≤ 5.25V (Note 2) 1 2 mV/V
Input Low Voltage VIL 0.8 V
Input High Voltage VIH 2.4 V
Input Current (A0, A1) IIL, IIH VA0, VA1 = VIL, VIH ±5 µA
Input Current (PDI) IIL, IIH VPDI = VIL, VIH ±25 µA
Positive Supply Voltage V+ 4.75 5.25 V
SYNC Supply Voltage DV+ 4.75 5.25 V
Negative Supply Voltage V- -4.75 -5.25 V
Positive Supply Current I+ 35 45 mA
SYNC Supply Current IDV+ 1 2 mA
Negative Supply Current I- 45 55 mA
Maximum FADJ ModulatingFrequency FF 2 MHz
SYNC OUTPUT
DUTY-CYCLE ADJUSTMENT (DADJ)
FREQUENCY ADJUSTMENT (FADJ)
VOLTAGE REFERENCE
LOGIC INPUTS (A0, A1, PDI)
POWER SUPPLY
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High-Frequency Waveform Generator
4 _______________________________________________________________________________________
__________________________________________Typical Operating Characteristics(Circuit of Figure 1, V+ = DV+ = 5V, V- = -5V, VDADJ = VFADJ = VPDI = VPDO = 0V, RL = 1kΩ, CL = 20pF, TA = +25°C, unless otherwise noted.)
0.11 100 1000
OUTPUT FREQUENCYvs. IIN CURRENT
10
100
MAX
038-
08
IIN CURRENT (µA)
OUTP
UT F
REQU
ENCY
(Hz)
10
1
1k
10k
100k
1M
10M
100M
100µF47µF
10µF
3.3µF
1µF
100nF
33nF
3.3nF
330pF
100pF
33pF
1.0
0-3 2
NORMALIZED OUTPUT FREQUENCYvs. FADJ VOLTAGE
0.2
0.8
MAX
038-
09
VFADJ (V)
F OUT
NOR
MAL
IZED
0
0.4
-2 -1 1
0.6
3
1.2
1.4
1.6
1.8
2.0
IIN = 100µA, COSC = 1000pF
0.85
NORMALIZED OUTPUT FREQUENCYvs. DADJ VOLTAGE
0.90
1.10
MAX
038-
17
DADJ (V)
NORM
ALIZ
ED O
UTPU
T FR
EQUE
NCY
1.00
0.95
1.05
IIN = 10µA
IIN = 25µA
IIN = 50µA
IIN = 100µA
IIN = 250µA
IIN = 500µA
2.0
-2.5-2.0 -1.0 1.0 2.5
DUTY-CYCLE LINEARITYvs. DADJ VOLTAGE
-2.0
1.0
MAX
038-
18
DADJ (V)
DUTY
-CYC
LE L
INEA
RITY
ERR
OR (%
)
0 1.5
0
-1.0
-1.5
-0.5
0.5
1.5
IIN = 10µAIIN = 25µA
IIN = 50µA
IIN = 100µA
IIN = 250µA
IIN = 500µA
60
0-3 2
DUTY CYCLE vs. DADJ VOLTAGE
10
50
MAX
038-
16B
DADJ (V)
DUTY
CYC
LE (%
)
0
30
20
-2 -1 1
40
70
80
90
100
3
IIN = 200µA
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High-Frequency Waveform Generator
_______________________________________________________________________________________ 5
SINE-WAVE OUTPUT (50Hz)
TOP: OUTPUT 50Hz = FoBOTTOM: SYNCIIN = 50µACF = 1µF
TRIANGLE-WAVE OUTPUT (50Hz)
TOP: OUTPUT 50Hz = FoBOTTOM: SYNCIIN = 50µACF = 1µF
SQUARE-WAVE OUTPUT (50Hz)
TOP: OUTPUT 50Hz = FoBOTTOM: SYNCIIN = 50µACF = 1µF
SINE-WAVE OUTPUT (20MHz)
IIN = 400µACF = 20pF
_____________________________Typical Operating Characteristics (continued)(Circuit of Figure 1, V+ = DV+ = 5V, V- = -5V, VDADJ = VFADJ = VPDI = VPDO = 0V, RL = 1kΩ, CL = 20pF, TA = +25°C, unless otherwise noted.)
TRIANGLE-WAVE OUTPUT (20MHz)
IIN = 400µACF = 20pF
FREQUENCY (Hz)
1M100k10k1k100 10M
FREQUENCY (Hz)
1M100k10k1k100 10M
SINE WAVE THD vs. FREQUENCY
MAX
038
toc0
1
FREQUENCY (Hz)
THD
(%)
1M100k10k1k
1
2
3
4
5
6
7
0100 10M
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High-Frequency Waveform Generator
6 _______________________________________________________________________________________
_____________________________Typical Operating Characteristics (continued)(Circuit of Figure 1, V+ = DV+ = 5V, V- = -5V, VDADJ = VFADJ = VPDI = VPDO = 0V, RL = 1kΩ, CL = 20pF, TA = +25°C, unless otherwise noted.)
FREQUENCY MODULATION USING FADJ
TOP: OUTPUTBOTTOM: FADJ
0.5V
0V
-0.5V
FREQUENCY MODULATION USING IIN
TOP: OUTPUTBOTTOM: IIN
FREQUENCY MODULATION USING IIN
TOP: OUTPUTBOTTOM: IIN
PULSE-WIDTH MODULATION USING DADJ
TOP: SQUARE-WAVE OUT, 2VP-PBOTTOM: VDADJ, -2V to +2.3V
+1V
0V
-1V
+2V
0V
-2V
SQUARE-WAVE OUTPUT (20MHz)
IIN = 400µACF = 20pF
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High-Frequency Waveform Generator
_______________________________________________________________________________________ 7
______________________________________________________________Pin Description
*The five GND pins are not internally connected. Connect all five GND pins to a quiet ground close to the device. A ground plane isrecommended (see Layout Considerations).
0
-1000 20 60 100
OUTPUT SPECTRUM, SINE WAVE(Fo = 11.5MHz)
-80
-20
MAX
038-
12A
FREQUENCY (MHz)
ATTE
NUAT
ION
(dB)
40 80
-40
-60
-10
-30
-50
-70
-90
10 30 50 70 90
RIN = 15kΩ (VIN = 2.5V), CF = 20pF, VDADJ = 40mV, VFADJ = -3V
0
-1000 10 30 50
OUTPUT SPECTRUM, SINE WAVE(Fo = 5.9kHz)
-80
-20
MAX
038
12B
FREQUENCY (kHz)AT
TENU
ATIO
N (d
B)20 40
-40
-60
-10
-30
-50
-70
-90
5 15 25 35 45
RIN = 51kΩ (VIN = 2.5V), CF = 0.01µF, VDADJ = 50mV, VFADJ = 0V
_____________________________Typical Operating Characteristics (continued)(Circuit of Figure 1, V+ = DV+ = 5V, V- = -5V, VDADJ = VFADJ = VPDI = VPDO = 0V, RL = 1kΩ, CL = 20pF, TA = +25°C, unless otherwise noted.)
-5V supply inputV-20
Sine, square, or triangle outputOUT19
+5V supply inputV+17
Digital +5V supply input. Can be left open if SYNC is not used.DV+16
Digital groundDGND15
TTL/CMOS-compatible output, referenced between DGND and DV+. Permits the internal oscillator to besynchronized with an external signal. Leave open if unused.
SYNC14
Current input for frequency controlIIN10
Phase detector output. Connect to GND if phase detector is not used.PDO12
Phase detector reference clock input. Connect to GND if phase detector is not used.PDI13
External capacitor connectionCOSC5
Duty-cycle adjust inputDADJ7
Frequency adjust inputFADJ8
Waveform selection input; TTL/CMOS compatibleA14
Waveform selection input; TTL/CMOS compatibleA03
PIN
Ground*GND2, 6, 9,11, 18
2.50V bandgap voltage reference outputREF1
FUNCTIONNAME
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_______________Detailed DescriptionThe MAX038 is a high-frequency function generatorthat produces low-distortion sine, triangle, sawtooth, orsquare (pulse) waveforms at frequencies from less than1Hz to 20MHz or more, using a minimum of externalcomponents. Frequency and duty cycle can be inde-pendently controlled by programming the current, volt-age, or resistance. The desired output waveform isselected under logic control by setting the appropriatecode at the A0 and A1 inputs. A SYNC output andphase detector are included to simplify designs requir-ing tracking to an external signal source.
The MAX038 operates with ±5V ±5% power supplies.The basic oscillator is a relaxation type that operates byalternately charging and discharging a capacitor, CF,
with constant currents, simultaneously producing a tri-angle wave and a square wave (Figure 1). The charg-ing and discharging currents are controlled by the cur-rent flowing into IIN, and are modulated by the voltagesapplied to FADJ and DADJ. The current into IIN can bevaried from 2µA to 750µA, producing more than twodecades of frequency for any value of CF. Applying±2.4V to FADJ changes the nominal frequency (withVFADJ = 0V) by ±70%; this procedure can be used forfine control.
Duty cycle (the percentage of time that the output wave-form is positive) can be controlled from 10% to 90% byapplying ±2.3V to DADJ. This voltage changes the CFcharging and discharging current ratio while maintainingnearly constant frequency.
High-Frequency Waveform Generator
8 _______________________________________________________________________________________
MAX038
OSCILLATOR
OSCILLATORCURRENT
GENERATOR
2.5VVOLTAGE
REFERENCE
OSC B
OSC ATRIANGLE
SINESHAPER
COMPARATOR
COMPARATOR
PHASEDETECTOR
MUX
COSC
GND
5
6CF
8
7
10
FADJ
DADJ
IIN
REF1
1720
2, 9, 11, 18
V+V-
GND
RF RD RIN
+5V
-5V
-250µA
SINE
TRIANGLE
SQUARE
A0 A1
OUT
SYNC
PDO
PDI
19
14
12
13
RL CL
3 4
DGND DV+15 16
+5V
*
= SIGNAL DIRECTION, NOT POLARITY
= BYPASS CAPACITORS ARE 1µF CERAMIC OR 1µF ELECTROLYTIC IN PARALLEL WITH 1nF CERAMIC.
*
*Figure 1. Block Diagram and Basic Operating Circuit
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A stable 2.5V reference voltage, REF, allows simpledetermination of IIN, FADJ, or DADJ with fixed resistors,and permits adjustable operation when potentiometersare connected from each of these inputs to REF. FADJand/or DADJ can be grounded, producing the nominalfrequency with a 50% duty cycle.
The output frequency is inversely proportional tocapacitor CF. CF values can be selected to producefrequencies above 20MHz.
A sine-shaping circuit converts the oscillator trianglewave into a low-distortion sine wave with constantamplitude. The triangle, square, and sine waves areinput to a multiplexer. Two address lines, A0 and A1,control which of the three waveforms is selected. Theoutput amplifier produces a constant 2VP-P amplitude(±1V), regardless of wave shape or frequency.
The triangle wave is also sent to a comparator that pro-duces a high-speed square-wave SYNC waveform thatcan be used to synchronize other oscillators. The SYNCcircuit has separate power-supply leads and can bedisabled.
Two other phase-quadrature square waves are gener-ated in the basic oscillator and sent to one side of an“exclusive-OR” phase detector. The other side of thephase-detector input (PDI) can be connected to anexternal oscillator. The phase-detector output (PDO) isa current source that can be connected directly toFADJ to synchronize the MAX038 with the externaloscillator.
Waveform SelectionThe MAX038 can produce either sine, square, or trian-gle waveforms. The TTL/CMOS-logic address pins (A0and A1) set the waveform, as shown below:
X = Don’t care.
Waveform switching can be done at any time, withoutregard to the phase of the output. Switching occurswithin 0.3µs, but there may be a small transient in theoutput waveform that lasts 0.5µs.
Waveform TimingOutput Frequency
The output frequency is determined by the currentinjected into the IIN pin, the COSC capacitance (toground), and the voltage on the FADJ pin. When
VFADJ = 0V, the fundamental output frequency (Fo) isgiven by the formula:
Fo (MHz) = IIN (µA) ÷ CF (pF) [1]
The period (to) is:
to (µs) = CF (pF) ÷ IIN (µA) [2]
where:
IIN = current injected into IIN (between 2µA and 750µA)
CF = capacitance connected to COSC and GND (20pF to >100µF).
For example:
0.5MHz = 100µA ÷ 200pF
and
2µs = 200pF ÷ 100µA
Optimum performance is achieved with IIN between10µA and 400µA, although linearity is good with IINbetween 2µA and 750µA. Current levels outside of thisrange are not recommended. For fixed-frequency oper-ation, set IIN to approximately 100µA and select a suit-able capacitor value. This current produces the lowesttemperature coefficient, and produces the lowest fre-quency shift when varying the duty cycle.
The capacitance can range from 20pF to more than100µF, but stray circuit capacitance must be minimizedby using short traces. Surround the COSC pin and thetrace leading to it with a ground plane to minimize cou-pling of extraneous signals to this node. Oscillationabove 20MHz is possible, but waveform distortionincreases under these conditions. The low frequencylimit is set by the leakage of the COSC capacitor andby the required accuracy of the output frequency.Lowest frequency operation with good accuracy is usu-ally achieved with 10µF or greater non-polarizedcapacitors.
An internal closed-loop amplifier forces IIN to virtualground, with an input offset voltage less than ±2mV. IINmay be driven with either a current source (IIN), or avoltage (VIN) in series with a resistor (RIN). (A resistorbetween REF and IIN provides a convenient method ofgenerating IIN: IIN = VREF/RIN.) When using a voltagein series with a resistor, the formula for the oscillator fre-quency is:
Fo (MHz) = VIN ÷ [RIN x CF (pF)] [3]
and:
to (µs) = CF (pF) x RIN ÷ VIN [4]
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High-Frequency Waveform Generator
_______________________________________________________________________________________ 9
A0 A1 WAVEFORM
X 1 Sine wave0 0 Square wave
1 0 Triangle wave
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age source (VIN) in series with a fixed resistor (RIN), theoutput frequency is a direct function of VIN as shown inthe above equations. Varying VIN modulates the oscilla-tor frequency. For example, using a 10kΩ resistor forRIN and sweeping VIN from 20mV to 7.5V produceslarge frequency deviations (up to 375:1). Select RIN sothat IIN stays within the 2µA to 750µA range. The band-width of the IIN control amplifier, which limits the modu-lating signal’s highest frequency, is typically 2MHz.
IIN can be used as a summing point to add or subtractcurrents from several sources. This allows the outputfrequency to be a function of the sum of several vari-ables. As VIN approaches 0V, the IIN error increasesdue to the offset voltage of IIN.
Output frequency will be offset 1% from its final valuefor 10 seconds after power-up.
FADJ InputThe output frequency can be modulated by FADJ,which is intended principally for fine frequency control,usually inside phase-locked loops. Once the funda-mental, or center frequency (Fo) is set by IIN, it may bechanged further by setting FADJ to a voltage other than0V. This voltage can vary from -2.4V to +2.4V, causingthe output frequency to vary from 1.7 to 0.30 times thevalue when FADJ is 0V (Fo ±70%). Voltages beyond±2.4V can cause instability or cause the frequencychange to reverse slope.
The voltage on FADJ required to cause the output todeviate from Fo by Dx (expressed in %) is given by theformula:
VFADJ = -0.0343 x Dx [5]
where VFADJ, the voltage on FADJ, is between-2.4V and +2.4V.
Note: While IIN is directly proportional to the fundamen-tal, or center frequency (Fo), VFADJ is linearly related to% deviation from Fo. VFADJ goes to either side of 0V,corresponding to plus and minus deviation.
The voltage on FADJ for any frequency is given by theformula:
VFADJ = (Fo - Fx) ÷ (0.2915 x Fo) [6]
where:
Fx = output frequency
Fo = frequency when VFADJ = 0V.
Likewise, for period calculations:
VFADJ = 3.43 x (tx - to) ÷ tx [7]
where:
tx = output period
to = period when VFADJ = 0V.
Conversely, if VFADJ is known, the frequency is givenby:
Fx = Fo x (1 - [0.2915 x VFADJ]) [8]
and the period (tx) is:
tx = to ÷ (1 - [0.2915 x VFADJ]) [9]
Programming FADJ FADJ has a 250µA constant current sink to V- that mustbe furnished by the voltage source. The source is usu-ally an op-amp output, and the temperature coefficientof the current sink becomes unimportant. For manualadjustment of the deviation, a variable resistor can beused to set VFADJ, but then the 250µA current sink’stemperature coefficient becomes significant. Sinceexternal resistors cannot match the internal tempera-ture-coefficient curve, using external resistors to pro-gram VFADJ is intended only for manual operation,when the operator can correct for any errors. Thisrestriction does not apply when VFADJ is a true voltagesource.
A variable resistor, RF, connected between REF (+2.5V)and FADJ provides a convenient means of manuallysetting the frequency deviation. The resistance value(RF) is:
RF = (VREF - VFADJ) ÷ 250µA [10]
VREF and VFADJ are signed numbers, so use correctalgebraic convention. For example, if VFADJ is -2.0V(+58.3% deviation), the formula becomes:
RF = (+2.5V - (-2.0V)) ÷ 250µA
= (4.5V) ÷ 250µA
= 18kΩ
Disabling FADJ The FADJ circuit adds a small temperature coefficientto the output frequency. For critical open-loop applica-tions, it can be turned off by connecting FADJ to GND(not REF) through a 12kΩ resistor (R1 in Figure 2). The -250µA current sink at FADJ causes -3V to be devel-oped across this resistor, producing two results. First,the FADJ circuit remains in its linear region, but discon-nects itself from the main oscillator, improving tempera-ture stability. Second, the oscillator frequency doubles.If FADJ is turned off in this manner, be sure to correctequations 1-4 and 6-9 above, and 12 and 14 below bydoubling Fo or halving to. Although this method doublesthe normal output frequency, it does not double theupper frequency limit. Do not operate FADJ open cir-cuit or with voltages more negative than -3.5V. Doingso may cause transistor saturation inside the IC, lead-ing to unwanted changes in frequency and duty cycle.
High-Frequency Waveform Generator
10 ______________________________________________________________________________________
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With FADJ disabled, the output frequency can still bechanged by modulating IIN.
Swept Frequency OperationThe output frequency can be swept by applying a vary-ing signal to IIN or FADJ. IIN has a wider range, slightlyslower response, lower temperature coefficient, andrequires a single polarity current source. FADJ may beused when the swept range is less than ±70% of thecenter frequency, and it is suitable for phase-lockedloops and other low-deviation, high-accuracy closed-loop controls. It uses a sweeping voltage symmetricalabout ground.
Connecting a resistive network between REF, the volt-age source, and FADJ or IIN is a convenient means ofoffsetting the sweep voltage.
Duty CycleThe voltage on DADJ controls the waveform duty cycle(defined as the percentage of time that the outputwaveform is positive). Normally, VDADJ = 0V, and theduty cycle is 50% (Figure 2). Varying this voltage from+2.3V to -2.3V causes the output duty cycle to varyfrom 15% to 85%, about -15% per volt. Voltagesbeyond ±2.3V can shift the output frequency and/orcause instability.
DADJ can be used to reduce the sine-wave distortion.The unadjusted duty cycle (VDADJ = 0V) is 50% ±2%;any deviation from exactly 50% causes even order har-monics to be generated. By applying a smalladjustable voltage (typically less than ±100mV) toVDADJ, exact symmetry can be attained and the distor-tion can be minimized (see Figure 2).
The voltage on DADJ needed to produce a specificduty cycle is given by the formula:
VDADJ = (50% - dc) x 0.0575 [11]
or:
VDADJ = (0.5 - [tON ÷ to]) x 5.75 [12]
where:
VDADJ = DADJ voltage (observe the polarity)
dc = duty cycle (in %)
tON = ON (positive) time
to = waveform period.
Conversely, if VDADJ is known, the duty cycle and ONtime are given by:
dc = 50% - (VDADJ x 17.4) [13]
tON = to x (0.5 - [VDADJ x 0.174]) [14]
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High-Frequency Waveform Generator
______________________________________________________________________________________ 11
MAX038
1µF
GND
COSC12
AO
V-
1811926GND GNDGND GND
5
8
10
7
1
13
14
15
16 N.C.
3
FADJ
IIN
DADJ
REF
OUT
DV+
DGND
SYNC
PDI
PDO
V+ A141720
–5V +5V
C2
1nFC3
1µFC1
12kΩR1
20kΩRIN
FREQUENCY
50ΩR2
N.C.
CF
19 SINE-WAVEOUTPUT
2 x 2.5VRIN x CF
Fo =
MAX038
100kΩR5
5kΩ R6
100kΩR7
100kΩR3
100kΩR4
DADJ
REF
+2.5V–2.5V
PRECISION DUTY-CYCLE ADJUSTMENT CIRCUIT
ADJUST R6 FOR MINIMUM SINE-WAVE DISTORTION
Figure 2. Operating Circuit with Sine-Wave Output and 50% Duty Cycle; SYNC and FADJ Disabled
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DADJ is similar to FADJ; it has a 250µA constant cur-rent sink to V- that must be furnished by the voltagesource. The source is usually an op-amp output, andthe temperature coefficient of the current sink becomesunimportant. For manual adjustment of the duty cycle, avariable resistor can be used to set VDADJ, but then the250µA current sink’s temperature coefficient becomessignificant. Since external resistors cannot match theinternal temperature-coefficient curve, using externalresistors to program VDADJ is intended only for manualoperation, when the operator can correct for any errors.This restriction does not apply when VDADJ is a truevoltage source.
A variable resistor, RD, connected between REF(+2.5V) and DADJ provides a convenient means ofmanually setting the duty cycle. The resistance value(RD) is:
RD = (VREF - VDADJ) ÷ 250µA [15]
Note that both VREF and VDADJ are signed values, soobserve correct algebraic convention. For example, ifVDADJ is -1.5V (23% duty cycle), the formula becomes:
RD = (+2.5V - (-1.5V)) ÷ 250µA
= (4.0V) ÷ 250µA = 16kΩVarying the duty cycle in the range 15% to 85% hasminimal effect on the output frequency—typically lessthan 2% when 25µA < IIN < 250µA. The DADJ circuit iswideband, and can be modulated at up to 2MHz (seephotos, Typical Operating Characteristics).
OutputThe output amplitude is fixed at 2VP-P, symmetricalaround ground, for all output waveforms. OUT has anoutput resistance of under 0.1Ω, and can drive ±20mAwith up to a 50pF load. Isolate higher output capaci-tance from OUT with a resistor (typically 50Ω) or bufferamplifier.
Reference VoltageREF is a stable 2.50V bandgap voltage reference capa-ble of sourcing 4mA or sinking 100µA. It is principallyused to furnish a stable current to IIN or to bias DADJand FADJ. It can also be used for other applicationsexternal to the MAX038. Bypass REF with 100nF to min-imize noise.
Selecting Resistors and CapacitorsThe MAX038 produces a stable output frequency overtime and temperature, but the capacitor and resistorsthat determine frequency can degrade performance ifthey are not carefully chosen. Resistors should bemetal film, 1% or better. Capacitors should be chosen
for low temperature coefficient over the whole tempera-ture range. NPO ceramics are usually satisfactory.
The voltage on COSC is a triangle wave that variesbetween 0V and -1V. Polarized capacitors are generallynot recommended (because of their outrageous tem-perature dependence and leakage currents), but if theyare used, the negative terminal should be connected toCOSC and the positive terminal to GND. Large-valuecapacitors, necessary for very low frequencies, shouldbe chosen with care, since potentially large leakagecurrents and high dielectric absorption can interferewith the orderly charge and discharge of CF. If possi-ble, for a given frequency, use lower IIN currents toreduce the size of the capacitor.
SYNC OutputSYNC is a TTL/CMOS-compatible output that can beused to synchronize external circuits. The SYNC outputis a square wave whose rising edge coincides with theoutput rising sine or triangle wave as it crosses through0V. When the square wave is selected, the rising edgeof SYNC occurs in the middle of the positive half of theoutput square wave, effectively 90° ahead of the output.The SYNC duty cycle is fixed at 50% and is indepen-dent of the DADJ control.
Because SYNC is a very-high-speed TTL output, thehigh-speed transient currents in DGND and DV+ canradiate energy into the output circuit, causing a narrowspike in the output waveform. (This spike is difficult tosee with oscilloscopes having less than 100MHz band-width). The inductance and capacitance of IC socketstend to amplify this effect, so sockets are not recom-mended when SYNC is on. SYNC is powered from sep-arate ground and supply pins (DGND and DV+), and itcan be turned off by making DV+ open circuit. If syn-chronization of external circuits is not used, turning offSYNC by DV+ opening eliminates the spike.
Phase DetectorsInternal Phase Detector
The MAX038 contains a TTL/CMOS phase detector thatcan be used in a phase-locked loop (PLL) to synchro-nize its output to an external signal (Figure 3). Theexternal source is connected to the phase-detectorinput (PDI) and the phase-detector output is taken fromPDO. PDO is the output of an exclusive-OR gate, andproduces a rectangular current waveform at theMAX038 output frequency, even with PDI grounded.PDO is normally connected to FADJ and a resistor,RPD, and a capacitor CPD, to GND. RPD sets the gainof the phase detector, while the capacitor attenuateshigh-frequency components and forms a pole in thephase-locked loop filter.
High-Frequency Waveform Generator
12 ______________________________________________________________________________________
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PDO is a rectangular current-pulse train, alternatingbetween 0µA and 500µA. It has a 50% duty cycle whenthe MAX038 output and PDI are in phase-quadrature(90° out of phase). The duty cycle approaches 100%as the phase difference approaches 180° and con-versely, approaches 0% as the phase differenceapproaches 0°. The gain of the phase detector (KD)can be expressed as:
KD = 0.318 x RPD (volts/radian) [16]
where RPD = phase-detector gain-setting resistor.
When the loop is in lock, the input signals to the phasedetector are in approximate phase quadrature, the dutycycle is 50%, and the average current at PDO is 250µA(the current sink of FADJ). This current is dividedbetween FADJ and RPD; 250µA always goes into FADJand any difference current is developed across RPD,creating VFADJ (both polarities). For example, as thephase difference increases, PDO duty cycle increases,the average current increases, and the voltage on RPD(and VFADJ) becomes more positive. This in turndecreases the oscillator frequency, reducing the phasedifference, thus maintaining phase lock. The higherRPD is, the greater VFADJ is for a given phase differ-ence; in other words, the greater the loop gain, the lessthe capture range. The current from PDO must also
charge CPD, so the rate at which VFADJ changes (theloop bandwidth) is inversely proportional to CPD.
The phase error (deviation from phase quadrature)depends on the open-loop gain of the PLL and the ini-tial frequency deviation of the oscillator from the exter-nal signal source. The oscillator conversion gain (Ko) is:
KO = ∆ωo ÷ ∆VFADJ [17]
which, from equation [6] is:
KO = 3.43 x ωo (radians/sec) [18]
The loop gain of the PLL system (KV) is:
KV = KD x KO [19]
where:
KD = detector gain
KO = oscillator gain.
With a loop filter having a response F(s), the open-looptransfer function, T(s), is:
T(s) = KD x KO x F(s) ÷ s [20]
Using linear feedback analysis techniques, the closed-loop transfer characteristic, H(s), can be related to theopen-loop transfer function as follows:
H(s) = T(s) ÷ [1+ T(s)] [21]
The transient performance and the frequency responseof the PLL depends on the choice of the filter charac-teristic, F(s).
When the MAX038 internal phase detector is not used,PDI and PDO should be connected to GND.
External Phase DetectorsExternal phase detectors may be used instead of theinternal phase detector. The external phase detectorshown in Figure 4 duplicates the action of the MAX038’sinternal phase detector, but the optional ÷N circuit canbe placed between the SYNC output and the phasedetector in applications requiring synchronizing to anexact multiple of the external oscillator. The resistor net-work consisting of R4, R5, and R6 sets the sync range,while capacitor C4 sets the capture range. Note thatthis type of phase detector (with or without the ÷N cir-cuit) locks onto harmonics of the external oscillator aswell as the fundamental. With no external oscillatorinput, this circuit can be unpredictable, depending onthe state of the external input DC level.
Figure 4 shows a frequency phase detector that locksonto only the fundamental of the external oscillator.With no external oscillator input, the output of the fre-quency phase detector is a positive DC voltage, andthe oscillations are at the lowest frequency as set byR4, R5, and R6.
MA
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High-Frequency Waveform Generator
______________________________________________________________________________________ 13
Figure 3. Phase-Locked Loop Using Internal Phase Detector
MAX038
GND
COSC12
A0V-
181192 6GND GND
15DGNDGND GND
5
8
10
7
1
13
3
FADJ
IIN
DADJ
REF
RD
OUT
PDI
PDO
V+
17
DV+
16 20
+5V -5V
C21µF
C11µF
CENTERFREQUENCY
50ΩROUT
CF
RPD
CPD
19
RFOUTPUT
A14
SYNC
14
EXTERNAL OSC INPUT
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High-Frequency Waveform Generator
14 ______________________________________________________________________________________
Figure 4. Phase-Locked Loop Using External Phase Detector
Figure 5. Phase-Locked Loop Using External Frequency Phase Detector
MAX038
GND
COSC12
A0V-
181192 6GND GND
15DGNDGND GND
5
8
10
7
1
13
3
FADJ
IIN
DADJ
REF
R2CW
R3
OUT
PDI
PDO
V+
17
DV+
16 20
+5V -5V
-5V
C21µF
C11µF
CENTERFREQUENCY
50ΩR1
R6GAIN
R5OFFSET
R4PHASE DETECTOR
EXTERNALOSC INPUT
C4CAPTURE
19 RFOUTPUT
A14
SYNC
14÷N
C3FREQUENCY
MAX038
GND
COSC12
A0V-
181192 6GND GND
15DGNDGND GND
5
8
10
7
1
13
3
FADJ
IIN
DADJ
REF
R2CW
R3
OUT
PDI
PDO
V+
17
DV+
16 20
+5V -5V
-5V
C21µF
C11µF
CENTERFREQUENCY
50ΩR1
R6GAIN
R5OFFSET
R4
C4CAPTURE
19
RFOUTPUT
A14
SYNC
14÷N
C3FREQUENCY
EXTERNALOSC INPUT
FREQUENCY PHASE DETECTOR
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High-Frequency Waveform Generator
______________________________________________________________________________________ 15
N4N3 N2
MC1
4515
1
N6
8.19
2MHz
MAX
427
N5
OUT1
OUT2
RFB
VREF
VDD
GND1
MX7541
N7 N8 N9 T/R
N12
N13
N10
N11
OSC O
UT
OSC I
N
LDNN1 N0 FV PD
VPD
RRA
2RA
1
RA0
PD1 O
UT V DD
V SS
F IN
35pF
20pF
1514
281
GND
BIT1
BIT2
BIT3
BIT4
BIT5
BIT6
BIT12
BIT11
BIT10
BIT9
BIT8
BIT7
MAX
038
A0 A1 COSC
GND1
DADJ
FADJ
OUT
GND V+ DV+
DGND
SYNC PD
I
PDO
VREF
V-
GND1
IINGN
D1
3.3M
ΩPD
V
PDR
3.3M
Ω33
k Ω 0.1µ
F
0.1µ
F
33k Ω
0.
1µF
0.1µ
F
7.5k
Ω
10kΩ
2 3
7 4
6
0.1µ
F0.
1µF+2
.5V
±2.5
V
35 pF
1011
0.1µ
F0.
1µF
0.1µ
F 50
.0Ω
100Ω
120
50Ω
, 50M
HzLO
WPA
SS F
ILTE
R22
0nH
220n
H
56pF
110p
F56
pF
50Ω
SIGN
ALOU
TPUT
SYNC
OUTP
UT
+5V
-5V
9 10
1 18
3 2
1
0V T
O 2.
5V
2N39
04
3.33
k Ω
2.7M
1k Ω
1kΩ
568 4
72N
39061N
914
2µA
to75
0µA
MAX
412
MAX
412
8.192MHz4.096MHz2.048MHz1.024MHz
512kHz256kHz128kHz64kHz32kHz16kHz8kHz4kHz2kHz1kHz
WAV
EFOR
MSE
LECT
FREQ
UENC
Y SY
NTHE
SIZE
R 1k
Hz R
ESOL
UTIO
N; 8
kHz T
O 16
.383
MHz
Figure 6. Crystal-Controlled, Digitally Programmed Frequency Synthesizer—8kHz to 16MHz with 1kHz Resolution
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High-Frequency Waveform Generator
Layout ConsiderationsRealizing the full performance of the MAX038 requirescareful attention to power-supply bypassing and boardlayout. Use a low-impedance ground plane, and con-nect all five GND pins directly to it. Bypass V+ and V-directly to the ground plane with 1µF ceramic capaci-tors or 1µF tantalum capacitors in parallel with 1nFceramics. Keep capacitor leads short (especially withthe 1nF ceramics) to minimize series inductance.
If SYNC is used, DV+ must be connected to V+, DGNDmust be connected to the ground plane, and a second1nF ceramic should be connected as close as possiblebetween DV+ and DGND (pins 16 and 15). It is notnecessary to use a separate supply or run separatetraces to DV+. If SYNC is disabled, leave DV+ open.Do not open DGND.
Minimize the trace area around COSC (and the groundplane area under COSC) to reduce parasitic capaci-tance, and surround this trace with ground to preventcoupling with other signals. Take similar precautionswith DADJ, FADJ, and IIN. Place CF so its connectionto the ground plane is close to pin 6 (GND).
___________Applications InformationFrequency Synthesizer
Figure 6 shows a frequency synthesizer that producesaccurate and stable sine, square, or triangle waves witha frequency range of 8kHz to 16.383MHz in 1kHz incre-ments. A Motorola MC145151 provides the crystal-con-trolled oscillator, the ÷N circuit, and a high-speed phasedetector. The manual switches set the output frequency;opening any switch increases the output frequency.Each switch controls both the ÷N output and anMX7541 12-bit DAC, whose output is converted to a cur-rent by using both halves of the MAX412 op amp. Thiscurrent goes to the MAX038 IIN pin, setting its coarsefrequency over a very wide range.
Fine frequency control (and phase lock) is achievedfrom the MC145151 phase detector through the differ-ential amplifier and lowpass filter, U5. The phase detec-
tor compares the ÷N output with the MAX038 SYNCoutput and sends differential phase information to U5.U5’s single-ended output is summed with an offset intothe FADJ input. (Using the DAC and the IIN pin forcoarse frequency control allows the FADJ pin to havevery fine control with reasonably fast response to switchchanges.)
A 50MHz, 50Ω lowpass filter in the output allows pas-sage of 16MHz square waves and triangle waves withreasonable fidelity, while stopping high-frequency noisegenerated by the ÷N circuit.
V+
PDI
SYNC
AO
DADJ
PDOFADJ
0.118"(2.997mm)
0.106"(2.692mm)
A1
COSC
GND
IINGND GND
DGND
DV+
GND
GND REF V- OUT
TRANSISTOR COUNT: 855SUBSTRATE CONNECTED TO GND
___________________Chip Topography
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses areimplied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
16 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
Package InformationFor the latest package outline information, go towww.maxim-ic.com/packages.
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This datasheet has been download from:
www.datasheetcatalog.com
Datasheets for electronics components.
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DEIC51515 Ampere Low-Side Ultrafast RF MOSFET Driver
Features • Built using the advantages and compatibility of CMOS and IXYS HDMOSTM processes • Latch-Up Protected • High Peak Output Current: 15A Peak • Wide Operating Range: 8V to 30V • Rise And Fall Times of <4ns • Minimum Pulse Width Of 8ns • High Capacitive Load Drive Capability: 2nF in <4ns • Matched Rise And Fall Times • 18ns Input To Output Delay Time • Low Output Impedance • Low Quiescent Supply Currentt Applications • Driving RF MOSFETs • Class D or E Switching Amplifier Drivers • Multi MHz Switch Mode Power Supplies (SMPS) • Pulse Generators • Acoustic Transducer Drivers • Pulsed Laser Diode Drivers • DC to DC Converters • Pulse Transformer Driver
Description TheDEIC515 is a CMOS high speed high current gate driver specifically designed to drive MOSFETs in Class D and E HF RF applications at up to 45MHz, as well as other applications requiring ultrafast rise and fall times or short minimum pulse widths. The DEIC515 can source and sink 15A of peak current while producing voltage rise and fall times of less than 4ns, and minimum pulse widths of 8ns. The input of the driver is fully immune to latch up over the entire operating range. Designed with small internal delays, cross conduction/current shoot-through is virtually eliminated in the DEIC515. Its features and wide safety margin in operating voltage and power make the DEIC515 unmatched in performance and value.
The DEIC515 is packaged in DEI's low inductance RF package incorporating DEI's patented (1) RF layout techniques to minimize stray lead inductances for optimum switching performance. The DEIC515 is a surface-mount device. (1) DEI U.S. Patent #4,891,686
Figure 1 - DEIC515 Functional Diagram
IN GND
IN
VCC IN
DGND
OUT
VCC
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DEIC51515 Ampere Low-Side Ultrafast RF MOSFET Driver
Absolute Maximum Ratings
Parameter ValueMaximum Junction Temperature 150oC Operating Temperature Range -40oC to 85oC Thermal Impedance (Junction To Case) θJC 0.13oC/W
Electrical Characteristics Unless otherwise noted, TA = 25 oC, 8V < VCC =VCCIN < 30V . All voltage measurements with respect to DGND. DEIC515 configured as described in Test Conditions.
Symbol Parameter Test Conditions Min Typ Max Units
VIH High input voltage VCCIN -2 V VIL Low input voltage 0.8 V VIN Input voltage range -5 VCC + 0.3 V IIN Input current 0V≤ VIN ≤VCC,VCCIN -10 10 µA VOH High output voltage VCC,VCCIN - .025 V VOL Low output voltage 0.025 V ROH Output resistance
@ Output high IOUT = 10mA, VCC = 15V 0.55 0.85 Ω
ROL Output resistance @ Output Low
IOUT = 10mA, VCC = 15V 0.35 0.85 Ω
IPEAK Peak output current VCC,VCCIN = 15V 15 A IDC Continuous output
current 2.5 A
fMAX Maximum frequency CL=2nF VCC,VCCIN =15V 45 MHz tR Rise time (1) CL=1nF VCC,VCCIN =15V VOH=2V to 12V
CL=2nF VCC,VCCIN =15V VOH=2V to 12V 2.5
4.1 ns
ns tF Fall time (1) CL=1nF VCC,VCCIN =15V VOH=12V to 2V
CL=2nF VCC,VCCIN =15V VOH=12V to 2V 2.5
3.9 ns
ns tONDLY On-time propagation
delay (1) CL=2nF Vcc=15V 17.4 18.5 ns
tOFFDLY Off-time propagation delay (1)
CL=2nF Vcc=15V 14.6 16 ns
PWmin Minimum pulse width FWHM CL=1nF VCC,VCCIN =15V +3V to +3V CL=1nF VCC,VCCIN =15V
6.4 8.2
ns ns
VCC,VCCIN Power supply voltage 8 15 30 V ICC Power supply current VIN = 0V
VIN = VCCIN 0 10
10 µA µA
Parameter Value
Supply Voltage 30V
All other Pins -0.3V to (Vcc,Vccin)+0.3V
Power Dissipation TAMBIENT≤25C Tcase≤25C
2W 100W
Storage Temperature -40C to 150C
Soldering Lead Temperature (10 seconds maximum)
300C
Input -5V to Vccin+0.3V
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DEIC51515 Ampere Low-Side Ultrafast RF MOSFET Driver
Lead Description - DEIC515
Note 1: Operating the device beyond parameters with listed “absolute maximum ratings” may cause permanent damage to the device. Typical values indicate conditions for which the device is intended to be functional, but do not guarantee specific performance limits. The guaranteed specifications apply only for the test conditions listed. Exposure
CAUTION: These devices are sensitive to electrostatic discharge; follow proper ESD procedures when handling and assembling this component.
Figure 2 - DEIC515 Package Photo And Outline
SYMBOL FUNCTION DESCRIPTION
VCC Output Supply Voltage Input for the positive output section power-supply voltage. These leads provide power to the output section. Both leads must be connected.
IN Input Input signal. OUT Output Driver Output.
PGND Power Ground The system ground leads. Internally connected to all circuitry, these leads provide ground reference for the entire chip. These leads should be connected to a low noise analog ground plane for optimum performance.
INGND Input Ground The input ground lead. This lead is a Kelvin connection internally to PGND. This lead must not be connected to PGND as excessive current can damage this lead.
VCCIN Supply Voltage Input for the positive input section power-supply voltage. This lead provide power to the input section. This lead should not be directly connected to VCC.
Bottom View
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DEIC51515 Ampere Low-Side Ultrafast RF MOSFET Driver
Typical Performance Characteristics
Figure 3a - Characteristics Test Diagram
Application The very high currents and high speeds inside the DEIC515 create very large transients. To avoid problems with false triggering, the input to the DEIC515 should be supplied via a common mode choke. This is a simple tri-filar winding on a small ferrite core. This prevents high speed transients from effecting the input signals, by allowing the input signals to follow the internal die potential changes without changing the state of the input.
++
--
Input
INVCC VCC IN OUT INGND GND
CL
VCC
L1
10µF 10µF
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DE275X2-102N06A
RF Power MOSFET
VDSS = 1000 V
ID25 = 16 A
RDS(on) = 0.8 ΩΩΩΩ
PDC = 1180 W
Symbol Test Conditions Maximum Ratings
VDSS TJ = 25°C to 150°C 1000 V
VDGR TJ = 25°C to 150°C; RGS = 1 MΩ 1000 V
VGS Continuous ±20 V
VGSM Transient ±30 V
ID25 Tc = 25°C 16 A
IDM Tc = 25°C, pulse width limited by TJM 48 A
IAR Tc = 25°C 6 A
EAR Tc = 25°C 20 mJ
dv/dt
IS ≤ IDM, di/dt ≤ 100A/µs, VDD ≤ VDSS, Tj ≤ 150°C, RG = 0.2Ω
5 V/ns
IS = 0 >200 V/ns
PDC (1) 1180 W
PDHS (1) Tc = 25°C, Derate 5.0W/°C above 25°C 750 W
PDAMB (1) Tc = 25°C 5.0 W
Symbol Test Conditions Characteristic Values TJ = 25°C unless otherwise specified
min. typ. max.
VDSS VGS = 0 V, ID = 3 ma 1000 V
VGS(th) VDS = VGS, ID = 4 ma 2.5 5.5 V
IGSS VGS = ±20 VDC, VDS = 0 ±100 nA
IDSS VDS = 0.8 VDSS TJ = 25°C VGS = 0 TJ = 125°C
50 1
µA mA
RDS(on) 1.6 Ω
gfs VDS = 15 V, ID = 0.5ID25, pulse test 2 7.5 S
VGS = 15 V, ID = 0.5ID25 Pulse test, t ≤ 300µS, duty cycle d ≤ 2%
RthJC (1) 0.25 C/W
RthJHS (1) 0.50 C/W
TJ -55 +175 °C
TJM 175 °C
Tstg -55 +175 °C
TL 1.6mm (0.063 in) from case for 10 s 300 °C
Weight 4 g
Features
• Isolated Substrate
− high isolation voltage (>2500V)
− excellent thermal transfer
− Increased temperature and power cycling capability
• IXYS advanced low Qg process
• Low gate charge and capacitances
− easier to drive
− faster switching
• Low RDS(on)
• Very low insertion inductance (<2nH)
• No beryllium oxide (BeO) or other hazardous materials
Advantages
• High Performance Push-Pull RF Package
• Optimized for RF and high speed switching at frequencies to >100MHz
• Easy to mount—no insulators needed
• High power density
♦ Common Source Push-Pull Pair ♦ N-Channel Enhancement Mode ♦ Low Qg and Rg ♦ High dv/dt ♦ Nanosecond Switching
DRAIN 1
SG1 SD1
GATE 1
DRAIN 2
SG2SD2
GATE 2
The DE275X2-102N06A is a matched pair of RF power MOSFET devices in a common source configuration. The device is optimized for push-pull or paral-lel operation in RF generators and amplifiers at frequencies to >65 MHz.
Note: All specifications are per each transistor, unless otherwise noted. (1) Thermal specifications are for the package, not per transistor
Unless noted, specifications are for each output device
Source 1 Source 2
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DE275X2-102N06A
RF Power MOSFET
Symbol Test Conditions Characteristic Values (TJ = 25°C unless otherwise specified)
min. typ. max.
RG 0.3 Ω
Ciss 1800 pF
Coss VGS = 0 V, VDS = 0.8 VDSS(max), f = 1 MHz
130 pF
Crss 25 pF
Td(on) 3 ns
Ton VGS = 15 V, VDS = 0.8 VDSS
ID = 0.5 IDM RG = 0.2 Ω (External)
2 ns
Td(off) 4 ns
Toff 5 ns
Qg(on) 50 nC
Qgs VGS = 10 V, VDS = 0.5 VDSS
ID = 0.5 ID25 20 nC
Qgd 30 nC
Cstray Back Metal to any Pin 21 pF
Source-Drain Diode Characteristic Values (TJ = 25°C unless otherwise specified)
Symbol Test Conditions min. typ. max.
IS VGS = 0 V 6 A
ISM Repetitive; pulse width limited by TJM 96 A
VSD 1.5 V
Trr 200 ns
IF = IS, VGS = 0 V, Pulse test, t ≤ 300 µs, duty cycle ≤ 2%
QRM IF = IS, -di/dt = 100A/µs, VR = 100V
0.6 µC
IRM 4 A
IXYS RF reserves the right to change limits, test conditions and dimensions.
IXYS RF MOSFETS are covered by one or more of the following U.S. patents:
4,835,592 4,860,072 4,881,106 4,891,686 4,931,844 5,017,508
5,034,796 5,049,961 5,063,307 5,187,117 5,237,481 5,486,715
5,381,025 5,640,045
(1) These parameters apply to the package, not individual MOSFET devices. For detailed device mounting and installation instructions, see the “DE-Series MOSFET Mounting Instructions” technical note on IXYS RF’s web site at www.ixysrf.com/Technical_Support/App_notes.html
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DE275X2-102N06A
RF Power MOSFET
10
100
1000
10000
0 100 200 300 400 500 600 700 800 900 1000
Vds in Volts
Capacitance in pF
Ciss
Coss
Crss
275X2-102N06A Capacitances vs Vds
S = S1 = Source1 S = S1 = Source1
S = S2 = Source2 S = S2 = Source2
G1 = Gate1
G2 = Gate2
D1 = Drain1
D2 = Drain2
Note: Sources S1, S2 are independent, having no com-mon connection between them for the package diagram.
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DE275X2-102N06A
RF Power MOSFET
102N06A DE-SERIES SPICE Model
The DE-SERIES SPICE Model is illustrated in Figure 1. The model is an expansion of the SPICE level 3 MOSFET model. It includes the stray inductive terms LG, LS and LD. Rd is the RDS(ON) of the device, Rds is the resistive leakage term. The output capacitance, COSS, and reverse transfer capacitance, CRSS are modeled with reversed biased diodes. This provides a varactor type response necessary for a high power device model. The turn on delay and the turn off delay are adjusted via Ron and Roff.
Figure 1 DE-SERIES SPICE Model
This SPICE model may be downloaded as a text file from the IXYS RF web site at www.ixysrf.com
Net List: *SYM=POWMOSN .SUBCKT 102N06A 10 20 30 * TERMINALS: D G S * 1000 Volt 6 Amp 1.6 Ohm N-Channel Power MOSFET M1 1 2 3 3 DMOS L=1U W=1U RON 5 6 .5 DON 6 2 D1 ROF 5 7 1.0 DOF 2 7 D1 D1CRS 2 8 D2 D2CRS 1 8 D2 CGS 2 3 1.9N RD 4 1 1.6 DCOS 3 1 D3 RDS 1 3 5.0MEG LS 3 30 .5N LD 10 4 1N LG 20 5 1N .MODEL DMOS NMOS (LEVEL=3 VTO=4 KP=2.3) .MODEL D1 D (IS=.5F CJO=10P BV=100 M=.5 VJ=.2 TT=1N) .MODEL D2 D (IS=.5F CJO=400P BV=1000 M=.6 VJ=.6 TT=1N RS=10M) .MODEL D3 D (IS=.5F CJO=400P BV=1000 M=.35 VJ=.6 TT=400N RS=10M) .ENDS
5 6
7
8
4
10 DRAIN
30 SOURCE
20 GATE
Don
Dcos
D2crs
D1crs
Rds
Ron
Doff
RoffRd
Lg
Ld
Ls
M32
13
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Doc #9200-0224 Rev 6 © 2006 IXYS RF