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Guidebook for TDK Inductors & Noise Suppression Components


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DC-DC converter

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Inductor's World

01

Inductor's World

Welcome to the wor ld of inductors!

You may wonder what exactly electroniccomponents are. Actually they are indispensableitems because electronic devices commonlyused in cell phones, PC's, TV sets, gamemachines, and so on are made up of electroniccomponents. Among them, inductors are a

group of hard workers, performing a varietyof tasksand were getting busier and busierwith the advent of the ubiquitous society inwhich people can easily access a mass ofinformation at any time and any place.Now let me introduce the members of ourinductor world and describe the excellent jobsthey are doing!

Nice to meet you! Im an inductor,one of electronic components.

Let's gointo the worldof inductors.

We pull outonly the desired

signals!

Noise suppressingcomponents

High-frequency inductors

We serveto stabilize

voltage!

Signal inductors

Power inductors

We arecontrolling

signals!

We arecontrolling

high-frequencysignals!

We serveto eliminate

noise!

Noise suppressioncomponents


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An inductor is actually just another name for a coil. Inductors are known as suchbecause, to use a technical term, they have inductive properties. That is, it can beobserved that when an electric current flows through a coil, it produces a magneticfield; or when a magnetic field passes through a coil, it produces an electric current.

What really is an inductor?

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Inductor's World

04

Inductor's World

A coil is a long wire that iswound around and around,many many turns.An electric current flowingthrough the coil can producemagnetic field lines just like amagnet.

Inductance

How caninductance (L)be increased?

By increasing thenumber of turns (n)

By using amagnetic core ()

By increasingcoil diameter (S)

Power of the inner coreto concentrate

magnetic field lines(magnetic permeability)

Number ofturns squared

Area ofthe ring

1/Lengthof coil

Coefficientcalculated byDr. Nagaoka,

a physicist

More magnetic field lines are produced when a core is placed inside acoil. This is because the core has the power to concentrate themagnetic field lines. The capability of producing magnetic field lines isreferred to as inductance (L). TDKs specialty is to develop corematerials having larger magnetic permeability(), that is, materialsthat can concentrate more magnetic field lines.

Core Coil without core Inductor (coil)

Various important electronic devices have been produced

using this property, including motors and generators.

Lkn2SLkn2S

1

A coil can transform itselfinto a magnet.

Electric current producesa magnetic field.

When a magnet is moved back and forththrough a coil, an electric current flowsthrough the coil.This is because the coil makes an electriccurrent so that it can produce anopposing magnetic field to counteract themagnetic field produced by the magnet.

A coil can generateelectricity.

Magnetic field producesan electric current.

An inductor is made more powerfulwhen a core is placed inside.


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Coils can store electrical energy in a form of magnetic energy using theproperty that an electric current flowing through a coil produces amagnetic field, which in turn produces an electric current. In other

words, coils offer a means of storing energy on the basis of inductivity(reactive magnetic flux).

Voltage regulating converters are stabilized when used in combinationwith inductors that can store magnetic energy,capacitors that can store electric energy, and a switch.

Choke meansto clog up

the flow of an alternatingelectric current.

Basic principle of choke-coils

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Inductor's World

06

Inductor's World

Electric

signals

PassZero frequency, that is,direct current isallowed to pass.

BrakingThe voltage of the passingsignals decreases withincreasing frequencies.

Signal stoppedThe voltage approaches zeroat further higher frequencies,finally stopping the signals.

Low-pass filter High-pass filter

Inductors can be used in combination with capacitors, whichcomplement the function of inductors, to form LC filters that canseparate the required signals from unwanted ones.

Function of coils depends on signal frequencies.This is because the higher the frequency,the less easily the signal flows.

High-frequencysignals areremoved whenthey passthrough thecapacitor.

Low-frequencysignals pass throughthe filter (low-pass)and are sent to theoutput.

Low-frequencysignals areremoved whenthey passthrough theinductor.

High-frequencysignals pass throughthe capacitor (highpass) and are sent tothe output.

OutputInput OutputInput

Noise

An electric current flows in the circuit,and energy is stored in the inductor(charging).

The energy stored in the capacitor is consumed(discharging), and the capacitor, in turn,stores energy and releases it.

Directcurrent

Diode

Semiconductor switching(current is turned ON andOFF at a high speed)

As soon as the current is turned off,the inductor produces magneticfluxes and releases the stored energy.

DC-DC converter (voltage step-down type)

Inductor(choke-coil)

Switching controls causethe output voltage to change

(basic principle ofDC-DC converters).

Capacitor

Coils can control signalsNoise is eliminated,or only the desired signals are allowed to pass.

Coils can store energy Voltage is stabilized.

Inductors can be roughly divided into two types according to their function.One is to control signals, and the other is to store electrical energy.Function of inductors

Reactive magnetic fluxes aregenerated in the coil to counteractthe changes in electric current.

Energy is stored in the coil becauseof the reactive magnetic fluxagainst the alternating current.

Low-pass filtersare also used to

remove high-frequencynoise.


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Signal inductors,wire-wound type

Signal inductors are the basic TDK inductors.They have small transmission loss (lowresistance), featuring a large current-handlingcapacity and high accuracy (narrow tolerance),thus providing a rich lineup that can satisfy the

specifications of our customers.

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Inductor's World

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Inductor's World

Power inductors,wire-wound type

Signal inductors,multilayer type

It was TDK who developed the worlds first inductors without winding.TDK has also developed high-frequency glass ceramic inductors and thelow-transmission loss Gigaspiral Multilayer Structure.

Noise suppression components,thin-film type

TDK has commercialized thin-film common mode filters to meet thedemand for smaller and thinner electronic devices, forming thin-film

of high flux density ferrite material and high-resolution pattern thinfilm coils on the basis ofstate-of-the-art nanotechnology.

MLK(Gigaspiral Multilayer Structure)

Divided,L-shaped ferrite core

Wire-wound coil

Externalelectrode

Drumcore

MLG

V-shaped ferrite corescorrespond to clothing!

TDK have developed special power inductors based on a newlydesigned unique structure, where a drum core is sandwiched by two

V-shaped cores, thus successfully achieving a large current capacityand reduction in calorific loss.

Ferrite core

Internalelectrode

Internalelectrode

Externalelectrode

Externalelectrode

Wire-wound coil

Exterior resin

Because there is a wide range of applications for and types of electronic devices,various types of inductors are required.TDK inductors are manufactured in many different shapes and sizes, including wire-wound or multilayer inductors, depending on where and how they are to be used.

Various types of inductors


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Inductor's World

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Inductor's World

Signalinductors(for controllingsignals)

Powerinductors(for stabilizingvoltage)

Noisesuppressioncomponents

GLF NLCV

SLF

ACM MEA

VLCF SLF

ACT ZJYS

MLF NLV TPL

SLF RLFVLF

ACM MMZTCM MEA

VLCF

MLG MLKMLG MLKMLG

GLF

MLK

GLF NL

Installation of

electric components

NLV MLF

Connection to

the Internet Automobaile LANs

High-speed

processing

One-segment

broadcasting

Increased

functionality

Mobile devices(mobile phones or music players)

Inductors are used forvarious equipmentand applications!

Applications andtypes of inductors

Family of inductors for various applications

AutomobilesPersonal computersand gamemachines

Television sets

Larger and thinnerDigitalization


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Trends in mobile phones and marketrequirements for inductorsIncreased number of ICs installed resulting from increase in functions

Increased demand for power inductorsHigh-density circuit board resulting from the increased number of components

Further reduction in size and weightHigh-resolution screen, speech quality assurance

Various noise suppression measures

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Inductor's World

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Inductor's World

Mobile phones are becoming more and more convenient multimedia

terminals as they feature a variety of functions, including cameras, color

liquid crystal displays, GPS navigation, digital money, one segment

broadcasting, and built-in compact HDDs. Inductors are also expected to

contribute to the further enhancement of multifunction mobile phones,

improved battery lives, and improved speech quality.

More and moreTDK inductors are being installed.

Cell phones

The smallest power coilin the industry

High-frequency noiseis absorbed andemitted as heat.

Noise suppressioncomponent in which four

LC filters are integratedinto a single package

Common mode filterdeveloped using thin-

film technology

LC's built-inT-shaped or-shaped

filter

Power supply circuits /DC-DC converters

Power inductors

VLF

Camera circuit section

Chip bead

MMZ

Flexible printedcircuit board (FPC)

LC filter array

MEA

Serial cable

Common mode array

TCM

Logic circuit

LC filter

MEM

EMC countermeasures at the LCD interface

As multifunction mobile phones are becoming popular, energysaving and noise suppression appear to be a problem. Our powerinductors VLF series are now widely used, because theinductors can reduce heating loss and handle a high level ofelectric current, thus contributing to energy saving.

The keys that support multifunction devices areenergy saving and noise suppression.

Serial transmission is the key to improving the design freedom ofmobile phones as the LCD display is often opened, closed, orreversed while in operation. To meet this requirement, we havedeveloped the TCM series of thin-film common mode noisesuppression filters.

To receive one segment broadcasting, we need to payattention not only to the communication frequency band (800MHz 2 GHz), but also the broadcasting frequency band (470 770 MHz). TDK has developed industrys first noise suppressioncomponents in its MEA series for one segment broadcasting.

The thinnest power coildeveloped using TDK'soriginal platingmethod

High-frequencycircuit

High-frequency

inductors

MLG

MLK

Transmission loss isreduced, and high-frequency signals arearranged.

An FPC with 40 or moreparallel signal wires isused as an interface tosend signals to the LCD.

Serial transmission has offered away to enable high-speed, high-capacity data transmission, and areduction in the number ofsignal wires. As a result, thehinge segment could be

narrowed, which, in turn,enabled free omni-directionalmovement. However, at thesame time, common mode noisesuppression measures areneeded.

However, paralleltransmission cannotmatch high-resolutionLCDs and increasedcontent.

Mainstream technique for noise suppressionmeasures in parallel transmission systems isto use LC filters (low-pass filters) combinedwith inductors and capacitors.

In serial transmission systems, common modefilters are indispensable devices to remove thecommon mode noise caused by the phase lagbetween differential signals.

Parallel transmission High-speed serial transmission

Faster transfer speed

Increase in designfreedom

Common modeNoise suppressionmeasures

Noisesuppression

measures

Noisesuppressionmeasures


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Trends in game machines andmarket needs for inductorsDemand for reduction in size and weight

Transition to smaller SMD componentsIncreased number of DC-DC converters resulting from increase in functions

Increased demand for power inductorsBuilt-in fast digital interface

Noise suppression measures using common mode filtersUse of wireless LAN

Increased number of high-frequency components such as high-frequency inductors

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Inductor's World

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Inductor's World

Graphics processing power for recent game machines with high-

definition 3D image processing is so high that it is almost comparable to

that of supercomputers. TDK inductors and noise suppression

components are used in new-generation game machines equipped with

blue-ray discs, HDDs, and wireless LAN capability.

CPU / Graphic processing unit /Image output circuit

Noise suppressioncomponents

Controller

Clamp filter

ZCAT

USB/IEEE interface

TCM

Impedance matching

Do not regard game machines as mere toys. Actually, a game machine is anintegrated mass of state-of-the-art electronic device technologies. Graphicsprocessing power is superior to that of PCs, and comparable to that of somesupercomputers. Some game machines will not only be equipped with HDDs, but

can also use next-

generation DVDs and blue-ray discs.As game machines progress,more and more informationprocessing capacity isrequired, and manyinductors are required fornoise suppression and signalcontrol. Next, we will learnabout impedance, which isindispensable for signalprocessing.

A game machine is an integrated body ofstate-of-the-art technology.

DVD circuit section /HDD circuit section

Power inductor

Signal inductor

GLFMLFMLGMLK

Power supply circuit /DC-DC converter

NLCV

Power inductoroptimized in terms ofmagnetic path design

and dimensions

Transmission loss is reduced,and high-frequency signals

are controlled.

Noise is reduced by onlypassing appropriate

signals through the cable.

Common mode filterfor high-speed datatransmission lines

High-frequency noiseis absorbed andemitted as heat.

ACM

MMZ

Impedance is the resistance to alternatingcurrent flow in an electrical circuit.Impedance can be roughly consideredfrom two directions, that is, 1) impedancetoward the signal source direction, and 2)

impedance toward the load direction.Impedance matching is required betweenthe two impedances. Unless the matchingbetween them is properly performed, thecircuit reflects back some of the signals,causing transmission loss, or distortssignals, preventing normal transmission ofdata. This is why we need signal inductorsto do their job. TDK has a rich lineup ofinductors, including the MLF seriesandthe high-frequency MLG seriesinductors, which satisfy our customersneeds for signal inductors.

SLFVLCF

Loadimpedance

Signal sourceimpedance

Signal coilsare used to perform

impedance matching.

Common mode filterdeveloped using thin-film technology

Decoupling coil for ICpower supply lines


Game machines


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Trends in television sets andmarket needs for inductorsReduction in panel size and thickness, emphasis on design

Transition from components with lead wire to SMDHigh-density circuit board

Less space for inductors (reduction in occupied area)Lower electric power consumption for energy saving

Lower direct-current resistance of power inductorsNetworking with digital equipment

Noise suppression of high-speed digital interface circuits

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Inductor's World

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Inductor's World

In place of CRT-based television sets, mainstream televisions are now

those with large-screen flat displays or plasma displays. After the

beginning of terrestrial digital broadcasting, not only screen size, but

also image quality and various optional functions are drawing

consumers attention.

Digital block / Digital tuner

Signal inductorNoise suppressioncomponents

MMZ

Differential transmission system andcommon mode noise

In Japan, analog broadcasting will finish at the end of July 2011, and digitalbroadcasting will follow. The well known white, red, and yellow cable connectorswill disappear, and all the transmission systems for television sets will be unified

with a High-Definition Multimedia Interface (HDMI). In other words, you can easilyconnect your television set to otherequipment through a single cable.HDMI uses a differential transmissionsystem to send high quality signals ata high speed without compressingthem. However, one problem iscommon mode noise. TDK tookadvantage of filter designtechniques and various advancedtechnologies that have beenaccumulated in the company, andhave successfully developed theACM-H and TCM-H seriescommon mode filters that have a farwider transmission band thanconventional filters.

Audio-visual equipment can beeasily connected to television sets usingthe next-generation interface, HDMI.

Noise can be divided into two types: normal mode and

common mode noise. Common mode noise is caused by thedifferential transmission system in which a pair of identicalsignals but of opposite polarities are sent.

NLCV

Power supply circuit /DC-DC converter

Power inductor

SLFVLCF

DVI/HDMIinterface

Common mode filter

ACMTCMCommon mode filtersare used to absorb andstabilize common modecomponents.

Occurrence of common mode noise

Phase lag

Difference in signal amplitude

Shaped waveform

Difference between rise timeand fall time

Output to HDMI terminal

Input to HDMI terminal

VHF/UHF input

VHF/UHF output

To antennaVHF/UHF input

Audio output

No white, red, and yellow cables are necessary.

Audio input

Power inductoroptimized in termsof magnetic pathdesign anddimensions

Decoupling coilfor IC powersupply lines

High-frequencynoise is absorbedand emitted as heat.

Common mode filterfor high-speed datatransmission lines

Common modefilter developedby using thin-filmtechnology

Transmission lossis reduced, and

signals arecontrolled.

Power cord

Clamp filter

ZCATNoise is reducedby only passingappropriatesignals throughthe cable.


Television sets

MLFGLF


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Trends in automobiles andmarket needs for inductorsPursuit of safety High-reliability, impact resistance, water resistanceECU installation in engine rooms 40~125C, high-reliabilityNoise suppression measures applied to in-vehicle LAN Common mode filters for automobiles

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Inductor's World

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Inductor's World

It is said that an automobile is made up of more than 20,000 components,

and the percentage of electronic components to the total number of

components is constantly increasing. Further, electronic components are

not allowed to malfunction because they are used in the vehicles to

which our lives are committed. What is needed is a highly reliable

product that can be used even in a harsh environment.

The Controller Area Network (CAN)BUS is one of the standards for in-vehicle LANs, which was designed toreduce the weight of automobiles. ACAN-BUS is less subject to noise

because it uses the differentialtransmission system, but commonmode noise still becomes a problem.The performance of TDKs ACTseries common mode filterhas beenenhanced, and they are now availablein a temperature range from 40 to150 C. The common mode filters aredesigned for good performance inharsh environments such as in engineroom. In addition, TDK has alsodeveloped theACM-V seriescommon mode filters for automobileECU power supply lines.

Common mode filters are indispensable forvehicles equipped with electrical components.

Moisture-resistant

small size power inductor

Heatproof SLFavailable up to 125

C

Moisture-resistantpower inductor

Heatproof RLFavailable up to 150

C

Transponder coil

TPLseries

High-speedCAN

Low-speedCAN

LIN

Safety use

MultimediaPower train / Body

Engine Control Unit (ECU), etc.

Heatproof ACTavailable up to 150

C

Common modefilter for in-vehicleLAN (CAN-BUS /FlexRay)

ACMGuaranteed inthe temperaturerange from -40 to 125

C.Used for noisesuppression in ECU powersupply lines.

Common mode filterfor in-vehicle LAN(CAN-BUS)

Common mode filter for MOST

Heatproof ACMavailable up to 105

C

Common mode filter formultimedia in-vehicle LAN (MOST)

Heatproof clamp filterfor automobile use

ZCAT

High-reliability large-

current three-terminal filter

ACHEMC filter for glass antennas

ZCD

High-frequency inductor

MLGMLK

Transponder(transponder coil, air-pressure sensor, etc.)

Transmitting andreceiving antenna

Car navigation, ETC, etc.

Tire pressure monitoring systems(TPMS), immobilizer

(motor vehicle antitheft systems),keyless entry systems, etc.Antenna coil for

receiving radio waves

Power inductor optimizedin terms of magnetic path

design and dimensionsPower inductoroptimized in termsof magnetic pathdesign anddimensions

Transmission loss is reduced,and high-frequency signals

are controlled.

Noise is reduced byonly passing appropriatesignals through the cable.


Automobiles

ZJYSTire-Pressure Monitoring System(TPMS)

needs transponder coilInstallation of the tire pressure surveillance system in North-Americanautomobiles was made obligatory in 2003. This surveillance system is awireless communication-based safe-driving system, and uses a pressure sensorto detect information on individual tires,which is wirelessly sent to the mainsystem in the drivers compartment. TDKsTPL series transponder coils are used asantenna coils to receive the signals fromthe sensors. In order to develop small,high-sensitivity, and reliable transpondercoils, advanced core technology and wire-winding techniques are required.

CAN is divided into three typesdepending on communication speed:

High-speed CAN (250k~500kbps)Low-speed CAN (around 125kbps)LIN (20kbps)

In the above picture, common mode filtersare used at the points marked with open circles.


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Magnetic core for inductors is where TDK started.

Long years of accumulated raw material technology

Advanced wire-winding technique,accurate to an order of microns

Layering technique that enabled realization ofinductors without wire-wound coils

It is virtually impossible to wind wires around very small coil cores, which are lessthan 1 mm long. TDK has developed machines that can wind wires not onlyaccurately, but also at a high speed around many tiny cores. For example, the high-precision automatic wire-winding machine (lower-left picture) is capable ofsimultaneously winding wires around a large number of coil cores. In addition, thegap between wires for common mode filters (lower-right picture) is controlled to an

order of microns. Two wires are

wound at the same time and at thesame space interval to produceeffective noise suppressioncomponents.

The first key point to raw material technology is composition. The basiccharacteristic of raw materials is decided by what materials are mixed at what rateand at what timing. The next point is firing. Not only temperature and firing time,but also the environment in the firing furnace (oxygen condensation) must be

accurately controlled. In addition, very small

cores must be very carefully formed to preventthem from becoming cracked or chipped.

As we have explained, coils are made by winding wires aroundcores, but TDK has upset this conventional wisdom. Ferrite materialis first processed to a paste, which is then formed as a thin sheet offilm. Next, a conductive pattern is printed on the film. Then, some

films with conductive patterns are stacked in layers, and finally thelaminated body is fired. Using this innovative method, TDKrealized the worlds first chip inductor in 1980. TDK inductors weremanufactured on the basis of TDKs original techniques from itsaccumulated know-how such as paste mixing, pattern printing,laminating, and firing.

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Inductor's World

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Inductor's World

The worlds first commercialized ferrite cores

Layered structure ofchip inductorsCrystal structure of ferrite

The magnetic material referred to as ferrite is widely used foralmost all inductor cores. TDK was founded to industrialize themanufacture of ferrite. Since then, TDK has launched productsthat serve to support our lives, including not only inductors, butcapacitors, magnetic heads, andrecording media, on the basis ofthe material technologycultivated through ferrite

manufacturing, as wellas process technologiesthat can takeadvantage of thosematerials.

Microscopic

molding

Ferrite core that isnarrower than the lead ina mechanical pencil

Originating

from TDK!

Advancedwire-winding

technique

This is where

TDK started.

Why are TDK inductors so competitive? The answer is because TDK has beenconsistently tackling various issues from raw material technology to processtechnology, and even the development of devices.TDKs advantages


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Inductor's World

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Inductor's World

Inductors are manufactured through various processes.Furthermore, expert know-how is required for each of thoseprocesses. Here, lets see how typical wire-wound products andmultilayer products are manufactured.

Wire-winding

Frame processing

Molding

A wire is wound around the core,and the terminals of the wire areconnected to the core.

The wire-wound core issandwiched by the frame.

Resin is poured over thecoil sandwiched by theframe.

The resin-covered coil is separated,and the frame is bent to formelectrodes

Core manufacturingAfter the processes of creatingthe fine particles, molding, andfiring, electrodes are formed onthe manufactured core (magneticcore).

Terminal treatment

Ferrite powder and resinare mixed to form ferritepaste.

Paste forming

The ferrite paste is flattenedinto a sheet form, andelectrodes are printed on it.

Sheet formingand printing

The stacked sheets are cut witha blade into the prescribed size,and perfectly fired in a furnace.

Both ends of the fired coil aredipped in electrode paste, andthen baked. Next, the entirebody of the coil is dipped inplating solution.

Electrode-printed ferrite sheetsare stacked in layers andpressed.

Multilayer process

Cutting and firing

Electrode coating and plating

Wire-winding type Multilayer type

Manufacturing process of in ductors


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TDK Inductors World

Date of Issue: September 5 2006 Publisher: Corporate Communications Department TDK Corporation

History of TDK Inductors and Noise Suppression Components

* Thi b h i i t d l d

1937 Worlds first ferrite coil cores launched

1962 TDKs first coils (peaking coils for TVs) launched

1962 TDKs first noise suppression device, Synchro V Socket, launched

1964 Linearity coils for color TVs launched1965 Line filters for color TVs launched

1972 Feed-through noise filter FN for communication instruments

and measuring equipment launched

1973 Dust-cored SF coils for noise filters launched

1977 Voltage step-up coil WT to drive sound-making devices in wristwatches launched

1978 Automatic manufacturing lines for small fixed coils (SP type) introduced

1980 The worlds first multilayer chip coil MLF launched

1982 Leadless coil NL launched

1983 Multilayer LC filter MXF launched

1985 Three-terminal signal noise filter ZJS launched

1988 Power chip coil SLF launched

1988 Multilayer integrated device MHD launched

1989 Clamp-type noise filter ZCAT launched

1990 Awarded the Okochi Memorial Technology Prize for developing technologies

and commercial production of multilayer integrated circuits

1991 Received the Science and Technology Merit Award under the Director-General of Science

and Technology Agencys Award for developing multilayer integrated circuits

1993 Thin-film chip coil NLU launched

1995 Multilayer LC filter array MEA (-type) launched

1996 High-frequency multilayer coil MLG launched

1998 High-frequency multilayer coil MLK launched

1999 Multilayer power bead MPZ launched

2000 Small common mode filter ACM2012 launched

2002 Wire-wound magnetic shield coil GLF1608 launched

2003 Multilayer chip bead MMZ0603 launched

2003 Thin-film common mode filter TCM launched2003 Transponder coil TPL for automobiles launched

2003 Power coil RLF7045/RLF10165 for automobiles launched

2003 Power coil VLF launched

2004 Multilayer chip bead MMZ0402 commercialized

2005 Power coil TFC commercialized (thinnest in the industry

and manufactured using our own plating method)

2006 High-frequency multilayer coil MLG0402 commercialized

(smallest multilayer ceramic coil in the industry)

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