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Passive components and circuits - CCP

Lecture 8

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Content

Passive electronic components – role Passive electronic components – resistors

Electrical properties Clasification Parameters Marking Codification

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Passive electronic components - role

A m p lifica tion(feed b ack , load , b ias )

R C L

H F tu n in g an d filte rin g(reson an t c ircu it)

C L

L F filte rin g(ac tive an d p ass ive filte rs )

R C L

C ou p lin g o f am p lifie r s tag esC

A tten u a tion an dim p ed an ce m atch in g

R

C u rren t sen s in g(in s tru m en ts )

R

Tim in gR C

A n a log s ig n a lp rocess in g

P u llin g u p an dp u llin g d ow n

R

Im p ed an ce m atch in gR

D ig ita l s ig n a lp rocess in g

N o ise su p p ress ionin s ig n a l lin e

(com m on m od e ch oke)L

N oise su p p ress ionin p ow er lin e

(fe rrite b ead , b yp ass cap )L C

E M I su p ress in g

C u rren t sen s in g(vo ltag e reg u la to r,

m oto r d rive r)R

E n erg y accu m u la tion(in d u c to r an d cap

in D C -D C con verto r)L C

C u rren t lim it in g(in L E D , laser, Z en er)

R

P ow erm an ag em en t

P ass ive com p on en tsap p lica tion s

Passive components consumption in the world, Billions

0

200

400

600

800

1000

1985 1989 1993 1999

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Passive components - dynamicsPentiumPentium 200Pentium II Pentium

Motherboard for 486 120 MMX 333MHz IIICapacitors Through hole ceramic

multilayer 58

SMD ceramic multilayer

151 190 300 600

Capacitors Array 32 140 200Through hole electrolithics with Ta

15 1

SMD electrolithics with Ta

37 80

Electrolithycs with Al 7 32 11 15Bypass 3Round 4

Total capacitors 73 159 257 492 895Resistors Through hole 92

SMD 146 188 635 1000Resistors array 64 148 346 300

Total resistors 92 210 336 981 1300

Total passive components

165 369 593 1473 2195

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Passive components/Active componentsSystem Total Passives Total ICs Ratio

Cellular Phones Ericsson DH338 Digital 359 25 14:1 Ericsson E237 Analog 243 14 17:1 Philips PR93 Analog 283 11 25:1 Nokia 2110 Digital 432 21 20:1 Motorola Mrl 1.8 GHz 389 27 14:1 Casio PH-250 373 29 13:1 Motorola StarTAC 993 45 22:1 Matsushita NTT DoCoMo 492 30 16:1 Consumer Portable Motorola Tango Pager 437 15 29:1 Casio QV10 Digital Camera 489 17 29:1 1990 Sony Camcorder 1226 14 33:1 Sony Handy Cam DCR-PC7 1329 43 31:1 Other Communication Motorola Pen Pager 142 3 47:1 Infotac Radio Modem 585 24 24:1 Data Race Fax-Modem 101 74 7:1 PDA Sony Magic Link 538 74 7:1

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Resistor – history and tendencies

1827 first resistor 1976 first integrated

resistors General tendencies of

evolution: Performances increases Dimensions decreases Costs decreases

22.5

6.5

6.3

0.6

1W resistors:

Axial leaded Chip

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Resistor – electrical properties The basic relation for

resistance calculus is:

l

Dw

t

S

lR

D

lffR

71061,2)()(2

1061,2)( 7

tw

lffR

])C20(1[ o

Ttw

lR

])C20(1[4 o

2

TD

lR

Write the values of the resistivities for the main materials used in electronics.

http://www.8886.co.uk/ref/resistivity_values.htm

http://hyperphysics.phy-astr.gsu.edu/hbase/Tables/rstiv.html#c1

http://www.istonline.org.uk/Handbook/40.pdf

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Resistor – equivalent electric scheme Due to the constructive

particularities, each resistor has a parasitic inductance and a parasitic capacitance besides the useful resistance.

Parasitic parameters must be taken into consideration at high frequencies.

R Lp

Cp

A B

ppp

pR RCjCL

LjRZ

21

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Problems

For the resistive voltage divider, determine the dividing factor if:

R1=1 K; R2=100 R1=100 K; R2=10 K R1=100 K; R2=1 K

How is the dividing factor modified with the frequency, if each resistor has a parasitic capacitance equal with 2 pF?

R1

R2 vovi

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Clasifications – constructiv criterion Discrete

Fixed Variable

Integrated Resistors arrays Resistor networks

Embedded (included in the structure) In the PCB level In the ceramic sublayer (multicip modules – MCM) In silicium with thin film technology In the integrated circuits

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Discrete resistors Fixed

Variable

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Integrated resistors Networks Areas

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Embedded resistors

Decrease of the total cost of manufacturing

Thermodynamic reliability Decrease of the

dimensions Compatibility between

different materials Values between 10 and

200K with tolerances under 10%.

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Clasification – liniarity criterion

Linear

Non-linear Thermistors

Varistors

Fotoresistors

t

V

.constR

( ) , temperatureR R t t

( ) , voltageR R v v

( ) , light fluxR R

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Clasification – technological criterion Pelicular resistors – are obtained by depositing a resistiv

material (aglomerated charbon, christalin charbon,metalic alloys, metalic oxids) into a thin layer (under 10m) on an isolator support.

Reeled (wired) resistors – are obtained wiring a metalic conductor on an isolator support. The technology is used for obtaining either precision resistors or high-power resistors.

Volume resistors – the resistiv element represents the whole body of the resistor.

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Clasification – geometric criterion

It concernes, in general, the way in which terminals are connected to the body of the resistor: With surface mounted

terminals (SMD); With axial terminals; With radial terminals;

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Parameters of fixed resistors Parameters that must be written on the body of the resistor

The nominal resistance Nominal tolerance value

Parameters written only on certain resistors The nominal dissipated power The temperature coeficient The superior limit voltage

Parameters that are not written (the nominal values’ domain, the nominal domain of temperature, the noise factor)

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Series of normalised values In practice, resistors are not manufactured with nominal

resistances in a continuous range of values. The solution used is that of a serie of normalised values.

Each serie is characterised by a certain tolerance. The nominal values of resistances are obtained from the

values of the normalised serie by multiplication with powers of 10.

A certain serie covers almost all the domain of possible values for resistances, taking into account that between two succesiv values of the serie the following relation holds :

)1()1( 1 tRtR ii

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Series of normalised values

The number of values in a series results, depending on tolerance, solving the equation on the right and taking the first superior integer for n.

The nominal values of a series are in a geometrical progression given by the following relation:

101

1

n

t

t

n

ii

r

rRR

R

1

0

0

10

;1

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Series of normalized values

The main normalized series are the following:

Values of the first three normalized series:

E6(20%); E12(10%); E24(5%);

E48(2%); E96(1%); E192(0,5%);

Normalized valuesSeries Tolerance Power 1/n Ratio 1 2 3 4 5 6 7 8 9 10 11 12 13

E6 20% 0.166667 1.47 1 1.47 2.15 3.3 4.7 6.81E12 10% 0.083333 1.21 1 1.21 1.47 1.78 2.15 2.61 3.3 3.83 4.7 5.62 6.81 8.25E24 5% 0.041667 1.1 1 1.1 1.21 1.33 1.47 1.62 1.78 1.96 2.15 2.37 2.61 2.87 3.3

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Choosing resistors depending on the tolerance In choosing resistors for an application an

important factor is their tolerance. The variation of functions of a circuit with

respect to the tolerances of the components is called sensitivity.

R1

R2

vI

vO

2

1;

2

1;

11

1

21;12

2

maxmin

tK

tK

tt

tK

RRRR

R

v

vK

I

O

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Nominal power, Pn Represents the maximum power that can be dissipated on

a resistor in a regime of prolonged functioning at a temperature equal to the nominal temperature Tn, without it modifying its parameters.

This parameter is written only for resistors with nominal power higher than 2W.

For this parameter there are 24 standardized values:

0,05W; 0,1W; 0,125W; 0,25W; 0,5W; 1W; 2W; 3W; 4W; .... 10W; 16W; ... 500W

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Low power resistors

For low power resistors (under 2W) the nominal power can be deducted from the dimensions of the resistor.

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Temperature coefficient

Apeares written on the body of the resistor only in case of precision resistors.

The parameter is defined as follows:

For most resistors this parameter can be considered constant.

dT

dR

RR 1

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The superior limit voltage, Vn

Apares written in the case of resistors designed for functioning at very high voltages .

For a usual resistor it can be deduced as follows:

For high value resistors, Vn can be limited under the previous value by reasons concerning the dielectrics breakdown.

RnPnVn

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The noise factor, F

Represents the value of the noise voltage that appears on the resistor when applying a 1V continuous voltage.

The noise voltage appears due to the disordered movement of the charge carriers in the conductor.

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Marking the resistors

Marking refers to the way in which the information written on the resistors is codified. Marking in the code of letters and figures Marking in the colors’ code

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Marking with the code of letters and figures Marking the nominal value is made using figures and letters

as multipiliers. The letter marks the presence of the decimal dot in the nominal value.

Multipliers: R=1; K=1.000 (kilo); M=1.000.000 (mega); G=1.000.000.000 (giga)

For tolerance marking one can use either the marking in clear (5%, 1%, etc.) or the letter codified one.

B0,1%; C0,25%; D0,5%; F1%; G2%; H2,5%; J5%; K10%; M20%

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Marking with the code of letters and numbers To avoid confusions between letters which have the

significance of both separator and tolerance, the ones that signify tolerance are written separately from the nominal value code (possibly on another line).

2K7 J

330KM

R33K

Value 2700, tolerance 5%

Value 330K, tolerance 20%

Value 0,33, tolerance 10%

The marking of the power and the temperature coefficient is made in clear for resistors for which is required to display these parameters.

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Marking with the code of letters and numbers for SMD resistors For SMD resistors, with very low dimensions, the following

code is used.(cod EIA-96).

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Marking with the code of colors

This type of codified marking, although more difficult to read, has the advantage that the writing is visible on the body of the resistor regardless of its position on the board.

The reading of the code is made starting with the colored ring that is the closest to a terminal or with the group of colored rings.

For resistors with nominal values from the series E6, E12, E24 and E48 the code has only four colored rings.

For resistors with nominal values from the series E96, E192 and with smaller tolerance, the code has five colored rings.

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Marking resistors – colors’ code

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Remarks Some colors have no significance for tolerance (orange,

yellow and white). In the case of the code with four rings, the only possible

colors for tolerance are red (2%), gold (5%) or silver (10%). The lack of the colored ring for tolerance means the

tolerance is 20%. Therefore, in this case the code will have only three colored rings.

Brown, black, red +gold =10•100 5%=1K 5%

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Codification of resistors Gives the information by which the resistors are described in

catalogs and therefore, also, in the lists of materials that are made. For resistors produced in Romania, the code has the following structure: Field I – contains three letters indicating the technological type; Field II – contains a figure with significance concerning the type

of capsule (the way the terminals are connected to the body); Field III – contains three figures indicating the nominal power; Field IV – contains a letter signifying the constructive variant;

In the material lists these codes are completed with the information written on the resistor (nominal value and tolerance).

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Codification of resistors – examples

RCG-1100-L 5K1 J

RPM-3050-L 1K 1%

General usage resistor with carbon film (coat) (RCG), with axial terminals (1), nominal power of 1W (100), reliable variant (L), 5,1K, tolerance 5% (J).

Resistor with metallic film (coat) (RPM), with radial terminals (3), nominal power 0,5W (050), reliable variant (L), 1K, tolerance 1%.

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Codification of resistors – examples for SMD resistors

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Codification of resistors In general, in the electric

schemes, next to the symbol of a resistor appears only its reference (R1, R205, etc.) and its nominal value (1K, 3K3, etc.). The power and the tolerance are mentioned only for components that have values different from the others.

This information regarding the codification appears on the equipment schemes as well (assembling plans).

R1 1R5 2W

R4

120

D1

DZ12

R2

1k2

VOD3

1N4001

D4

1N4001

R3

120

Q3BD136

R55k761%

Q2BD135

0

R66k341%

VIQ12N3055

D2

PL5V6

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Problems For a 100 resistor, the tolerance is t=±0,1% at a

reference temperature T0=20 oC. The resistor has a temperature coefficient T=±20ppm/oC. The environmental temperature is between [-30 oC; +90 oC].

1. Considering that, due to the dissipated power, the resistor body is heated with 50 oC, which is the global tolerance of the resistor?

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Problems2. The resistor body temperature is modified based on the

following relation:

where TA is environment temperature, and P is the dissipated power. On the resistor is applied a voltage with the waveform presented in the figure bellow. How can be the maximum amplitude of the pulses in order to have the global tolerance lower than tG=±0,3%?

PTT A 60

vR

t[m s]

0 3 5 8 10

V

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Problems

3. How is the maximum temperature of environment if the voltage applied on the resistor is sinusoidal with 7V amplitude, and the global tolerance is lower than tG=±0,3%?

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Dividing factor for R1=1 K şi R2=100

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Dividing factor for R1=100 K şi R2=10 K

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Dividing factor for R1=100 K şi R2=1 K