Discretes Semiconductors

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IntroductionIntroduction This training material contains Basic information

about Discrete Semiconductors and how they areused.

It is simplified for use such that a technicalbackground is not required for understanding.You will learn specifically about Types of

Discrete Semiconductors. Information will enable you to properly identify

and categorize types of Discrete semiconductorsbased on product characteristics.


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Topics CoveredTopics Covered

1. Introduction to Semiconductors

2. Discrete Semiconductors

3. Integrated Circuits

4. Packaging

5. Glossary of Terms

6. Self-test


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Course OutlineCourse Outline

PART ONE 2hrs

Introduction to Semiconductors

Discrete Semiconductors

PART TWO 2 hrs

Integrated Circuits

PART THREE 2 hrs

Packaging

Glossary of Terms

Self-test


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PART ONEPART ONE

Introduction to Semiconductors



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1. Introduction to Semiconductors1. Introduction to Semiconductors

1.1 What are semiconductors?

1.2 How are semiconductors made?

1.3 What do semiconductors do?

1.4 Who makes semiconductors?

1.5 Who buys semiconductors?

1.6 Types of Semiconductors


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1.1 What are Semiconductors?1.1 What are Semiconductors?

Materials with conductivity between conductorand insulator.

Conductor Semiconductor Insulator

Copper Silicon Plastics

Aluminum Germanium Rubber

Gold Gallium Arsenide Ceramics


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First transistor made by Schockley, Brattain & Bardeen in 1947

First transistor was made in 1947First transistor was made in 1947


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1.2 How are semiconductors made?1.2 How are semiconductors made?

SandCrystal

Growth

Ingot

Slicing

Wafer

Polish

DiffusionPhoto/

EtchDoping

Metal/

Test

Wafer

SawPackaging Final Test


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1.3 What do Semiconductors do?1.3 What do Semiconductors do?

SensingInput

Isolation&

Protection

WorkOutput

Power

DecisionMaking

LogicSmall Signal

ZenersRectifiers

LogicAnalog

ZenersRectifiers

PowerTransistorsRectifiersThyristors

IGBTs

AnalogRectifiers

Power Transistors

Isolation&

Protection

They perform many functions in every electronic system


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SIM/SAM Smart-card interfaceMC33560

NCN6000*NCN6010*NCN6011*

RF Power Amplifier

Control & Supply,Op. Amps

MC33170MC33202MC33501

BatteryManagementMC33349MC33340/2

O Voltage Regulationulti-Output, Inductive load78LC/FC/PCxx MC3326333275/375 MC3376533283 MC33761 MC33762

nergy Conversion

ase-band SupplyCD BiasC33463 MC33466C34280 MC7660AX828/9 MC1121

Voltage SupervisoryNCP300/1/2/3/4/5

NCP345MAX809/810

I/O ProtectionNCP345

For Example


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Applications For Semiconcuctor Products

Automotive Personal Digital Assistant Printer Control BoardABS & Traction Control Audio DC-DCCar radio Backlight control ESD/Transient ProtectionConvenience control Interface ON/OFF Control

DC Motor Control & H-bridge LED Drivers SensorsEngine Management Li-ion Charge control Stepping Motor DriversIgnition System Li-ion/Ni-MH DC-DC Converters USB InterfaceLIN Transceiver Li-ion/Ni-MH LDOsMotor Fan ON/OFF Control Settop Box

PA Control Clock DistributionDesktop Computers USB Interface Clock GenerationGraphics Card Voltage Supervisory General Purpose LogicPower Delivery PLL

Silver Box Power Supplies SAM/SIM InterfaceUSB Interface High Watt (>100W) USB Interface

Low Watt (


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Application: Cellular Phones

Average: 10 to 70 components in theAverage: 10 to 70 components in the

typical cell phonetypical cell phone


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1.4 Who makes Semiconductors?1.4 Who makes Semiconductors?

FairchildIntegrated Device Tech

VLSI TechMaximCirrus LogicATI TechAltera

QualcommHarrisXilinxOkiHPAtmelConexantAnalog Devices

LG SemiconSonyHyundaiLSI LogicRohmMicron TechSharpSanyoNationalMatsushitaAMD

IBMLucent

MitsubishiFujitsuSiemens

STMPhilipsHitachiSamsung

ToshibaTI

MotorolaNEC

Intel

ON Semiconductor

RelativeSharePosition

Top 40 Semiconductor suppliers in 1999


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1.51.5 Who buys Semiconductors?Who buys Semiconductors?

OEMs Original equipment manufacturers. Such as IBM, Apple, Dell,

Ford, Chrysler, Nokia, Motorola etc.

Distributors For Resale to low volume users. Eg Arrow, Avnet, etc

EMSIs Contract Manufacturers who build equipment for the OEMs.

Eg Selectron etc.Individuals For personal use

EMSIs9%

Distributors45%

45%

9%

46

OEMs46%

Typical Semiconductor CoRevenue By Customer


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1.6 Types of Semiconductors1.6 Types of Semiconductors


These are devices that perform a single function such asswitching, rectification or amplification. Examples are

diodes, transistors and thyristors

Integrated Circuits

These are combination of discrete elements on a single pieceof silicon performing single or multiple functions such asvoltage regulation, synchronous rectification, storage ofinformation in memory, high speed switching or powermanagement. Examples are analog switches, logic gates,operational amplifiers and LDO voltage regulators.


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Worldwide SemiconductorMarket

Product Breakdown (1999)

Source: WSTS

Total Semiconductors - $149.4B

Integrated Circuits - $130.2B

Digital - $108.1B

MOS - $107.1B

Memory

$32.3B

DRAM$20.7B

Discrete&Opto$19.2B

Analog$22.1B

Diodes,Rectifiers.Transistors,etc.$13.3B

Optoelectronics - $5.8B

Amp.,Interface,etc.$16.2B

SpecCons$5.9B

Digital Bipolar - $1.0BLogic

$23.2BMicro - $51.7B

SRAM $4.7B

Non-volatileMemory:ROMsEPROMEEPROM

$2.0B

Microproc-

essor -

$27.2B

Micro-

control-

ler

$14.1B

Micro-

peri-

pheral

$10.4B

DSP $4.4B

OtherLogic

$10.5B

ASIC

Gate Arrays,FPL Standardcells

$12.7B

Flash $4.6B

MixedSignal

Flash $4.6B


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2.2. Discrete SemiconductorsDiscrete Semiconductors

2.1 Diodes2.1.1 Small signal diodes

2.1.2 Rectifiers

2.1.3 Zener

2.1.4 TVS

2.2 Transistors2.2.1 Small Signal Bipolar Transistors

2.2.2 Bipolar Power Transistors

2.2.3 Field Effect Transistors (FET)

2.3 Mosfets

2.3.1 Mosfet Operation2.3.2 Small Signal & Power Mosfets

2.3.3 SmartDiscrete

2.4 IGBT

2.5 Thyristors


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Common terminologyCommon terminology

Name Symbol Simple meaning (Units)Current I Movement of electrons. (Amperes, A)

Voltage V Potential that causes current to flow (Volts, V)

Power P Current X Voltage. Total Force applied (Watts, W)Resistance R Resistance to current flow. (Ohms)


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2.12.1 DiodesDiodesA diode consists of a PN junction and has

two(2) terminals, an anode(+) and a

cathode(-). Current flows in only one

direction: from anode to cathode within the

diode.

An ideal diode is like a light switch inyour home. When the switch is closed,

the circuit is completed; and the light

turns on. When the switch is open, there

is no current and the light is off.

Anode (+)

Cathode (-)

(+)(-)


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2.12.1 Diode CharacteristicsDiode Characteristics

Important diode specifications are:

(a) Reverse voltage, Vr

(b) Rated forward current, If

(c) Forward voltage drop, Vf

(d) Leakage current, Ir

(e) Package style

(f) Reverse recovery time, trrVf

Generally, Diodes are used in waveshaping(rectification) applications. This involves

the alteration of AC signals by passing

certain portions of the signal and blocking

the rest.


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2.1.12.1.1 Small Signal DiodesSmall Signal Diodes

These are diodes which are rated to handle less than 1W of Power.

Power >1W can destroy these diodes.

There are Schottky, switching and Tuning diodes with differentcharacteristics which define their special functions.

Schottky diodes have very low forward drop (Vf) and are used in highspeed switching applications.

Switching diodes are used in general purpose switching applications

Tuning diodes are used for FM radio, TV Tuning and high frequencycontrol applications


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Small Signal Diode CharacteristicsSmall Signal Diode Characteristics

Schottky

Diode

Switching

Diode

Tuning

Diode

Max PowerRating (W)

1 1 1

Special

Characteristics

Low forwarddrop (Vf)

General purpose SensitiveCapacitance-

voltage response(High Q)

Typical use High speedswitching

General purposeswitching

FM Radio & TVTuning


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2.1.22.1.2 RectifiersRectifiers

These are diodes which are rated to handle very high Power. Some of these

diodes can handle up to 1000W or more.

Schottky rectifiers handle high current and moderate voltage and can switch

very fast efficiently. Silicon Bipolar rectifiers (standard & fast recovery) can

handle high voltage and moderate current but switch slower. They can be madeto switch faster (Ultrafast and Ultrasoft) but will also have reduced conduction

efficiency.

Rectifiers convert AC signals to DC and vice-versa by process called

rectification. They are generally used in Power supplies, high frequency

switching applications including motor speed control and for circuit protection.


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Rectifier CharacteristicsRectifier Characteristics

Rectifiers

Schottky Std Recovery FastRecovery

Ultrafast Ultrasoft

Power Rating (W) Up to 1000High I,

Low V

Up to 1000

High V,

Low I

Up to 1000

High V,

Low I

Up to 1000

High V, Low I

Up to 1000

High V,

Low I

SpecialCharacteristics

Low Vf & fastswitching

ModerateRecovery speed

(trr)

Fast Recoveryspeed (trr)

Very Fast

Recoveryspeed (trr)

Very fast andcontrolled

Recovery (Qrr)

Typical Use Low Voltagehigh freq

rectification

General Purpose DC Powersupply,

Ultrasonic &low RF systems

High VoltageHigh Freq

rectification

PFC, Variablespeed motor

contol


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2.1.3 Zener Diode2.1.3 Zener Diode

Zener diodes are designed to have a specific reverse breakdown voltage bycareful doping of the junction

The Zener acts as a voltage regulator by operating under reverse bias

conditions Any voltage higher than the reverse breakdown, Vz, isdissipated across the junction.

The zener can recover from reverse breakdown as long as the maximumPower rating is not exceeded.

Low Power (1W) zeners are available in radial or axial leads while medium(10W) and high power (20W) are usually in metal cases for attachment toheat sinks.


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2.1.4 TVS Diodes2.1.4 TVS Diodes (Transient Voltage Suppressor)(Transient Voltage Suppressor)

A TVS Diode limits over voltages caused by current surges and dissipates high transientpower with very short response times

(1 pico sec).

Unidirectional

Bi-directional

D.C. Current Protection

A.C. Current Protection

Additional important specifications are:

(a) Vcl; max protection voltage

(b) Ipp; Peak pulse current

(c) Ppp; Peak pulse power (Ipp x Vcl)

(d) Tcl; Time to avalanche

(e) Ifsm: Rated Forward pulse current


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2.22.2 TransistorsTransistors

The transistor is an arrangement of Semiconductor materials that share commonphysical boundaries. In n-type silicon, impurities, called dopants are introduced

resulting in excess of electrons or negative charges. In p-type silicon the dopants

lead to a deficiency of electrons and therefore an excess of positive charge carriers

or holes. When electric potential on the n or p sections are properly set, current

flow can be turned ON or OFF and signals can be magnified or changed.

The Junction Transisor The Field Effect Transistor The metal-oxide FET

(Bipolar Transistor) (JFET)

PPN N

Emitter

Base

Collector

Gate 1

Gate 2

P

P

NSource Drain

Source

P

N N

DrainGateNPN


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2.2.1 Small Signal Bipolar Transistors2.2.1 Small Signal Bipolar Transistors

Small Signal Bipolar

Transistors are NPN or

PNP transistors which

have max power rating

Of 1 Watt or less.

In contrast, Bipolar

Power transistors can

handle considerablymore power.


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Small Signal Bipolar Transistors-TypesSmall Signal Bipolar Transistors-Types

GeneralPurpose

Switching BRT Darlington RadioFrequency

Characteristic Wide range Fast switchingwith low losses

Built-in resistornetwork

Cascade of twoor moretransistorsconnected to

increase currentgain

High Frequencyoperation withhigh Ft

Typical Use Signalamplification

Amplification &switching

Save boardspace. No needfor externalresistor

Power Supplieswhere highcurrent gain isrequired

VHF/UHF signalamplification.TV/Radio


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NPN Bipolar Transistor BiasingNPN Bipolar Transistor Biasing

Fwd biased Junction Reverse biased Junction


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NPN Transistor OperationNPN Transistor Operation

The P-type base is set betweenthe N-type emitter and collector

There are two P-N junctions thatcan communicate

Base-emitter junction is forwardbiased and base-collectorjunction is reverse biased.

Electrons are injected from theemitter into the base, diffuse tothe base-collector junction andfall down the steep hill into thecollector.

In the base region, some of theelectrons recombine with holes inthis p-type region


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Amplification in NPN TransistorAmplification in NPN Transistor

The emitter current, (Ie) represents 100% of thecurrent flow in the transistor.

Only 2-5% of the current flow is base current (Ib)

The remaining 95-97% is collector current (Ic)

Ie = Ib + Ic

The amount of current leaving the emitter is only

a function of the small emitter-base bias (Vbb)

A small change in the emitter-base bias causes

a large change in the collector current since mostof the emitter current ends up in the collector.

This is the principle of AMPLIFICATION.


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NPN Transistor AmplificationNPN Transistor Amplification

Important parameters: Current Gain or Beta, hfe = Change in Ic/Change in Ib

Transconductance, gm = Change in Ic/Change in V

I

vbe

Q-point

time

time

Vbe

cI

Input Signal

Output Signal


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2.2.22.2.2 Bipolar Power TransistorBipolar Power Transistor

Bipolar Power transistors differ from smallsignal Bipolar transistors in that they can

handle more power.They are used in high power audio

amplification as high frequency drivers orgeneral purpose switching in regulators,

converters and power amplifiers


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Small Signal vs Power Bipolar TransistorSmall Signal vs Power Bipolar Transistor

Small Signal

Bipolar transistor

Power Bipolartransistor

Ptmax (W)< 1 1.25 - 300

Ic (Amp) 0.05 3 0.3 - 60

Vceo (Volt) 5 - 450 25 - 500

Hfe min 15 500 5 - 3000

Hfe max 45 - 1500 25 - 20000

Ft min (MHZ) 15 - 450 .08 - 65


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JFET OperationJFET Operation

Drain to source Voltage (Vds) changes the resistance in the channel by reducing the channel size

(depletion) which in turn reduces the amount of current flow. As the Vds increases, it reaches a

point, where the channel is closed off and current flow stops. Gate to source voltage (Vgs)

has the same effect and so the channel can be closed from both Vds and Vgs


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JFET OperationJFET Operation

Important Parameters:

Idss The value of drain current, IDwhich flows when Vgs = 0v

Vp - The Pinchoff Voltage. This is the value of Vds at which increase in the Vds does not

produce an increase in ID.. When Vgs is increased, the Vp value is reached sooner as the Vgs

adds to the drain-to-source value pinching off the channel faster.

JFETs are used in audio and RF amplification and for high frequency switching functions.


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JFET ParametersJFET Parameters

Parameter Typical Values

IDSS (uA) 1000-150000

VBR(DSS) (V) 25-40

Ciss (pF) 4 85

Crss (pF) 1 - 15


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2.3 Mosfets2.3 MosfetsMosfets are metal-oxide semiconductor Field effect Transistors

Source

Gate

Drain

N

PP

A Mosfet is a sophisticated,

Solid-state ON/OFF switch.

Low Voltage, Low rdson Mosfets

are used extensively for

Power management in Portable &

Battery powered products (Computers,

Printers, Cellular Phones).

They are also used in low voltage,

high speed switching

applications in Power supplies,

Converters and motor controls.


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2.3.1 Mosfet Operation2.3.1 Mosfet OperationWhen the gate of the Mosfet is open by the

appropriate gate voltage, Vgs, current, IDflows from source to drain as shown.

The Gate Voltage required to turn the

Mosfet ON is called the Threshold

Voltage (Vth).

If the threshold voltage is not reached, the

Mosfet remains in the OFF state. In this

way, a Mosfet is a simple ON/OFF switch,

just like the light switch in your house.

The amount of resistance to current flow in

the ON state is called Rds(on).

The Mosfet blocks any applied drain-to-

source voltage, until the rated VBDSSwhen appreciable drain-to-source current,

IDSS flows.

Gate

N

PP

Drain

Source

Current Flow ID


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2.3.2 Small Signal & Power Mosfets2.3.2 Small Signal & Power Mosfets

Small Signal Mosfet Power Mosfet

VBDSS (Volts) 8 - 240 8 - 200

Rds(on) (mohm) 160 14000 4.6 - 1000

IDmax (Amps) .115 - 2 0.9 - 110

PD max (Watts) .15 1.5 0.4 - 300

Power Mosfet Rds(on) is a very important parameter and has been continouslyreduced as the Technology has improved. This parameter determines how muchresistance exists to current flow. Low rdson is good because it minimizes the needfor expensive heat sinks.


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2.3.32.3.3 SmartDiscretesSmartDiscretes

A SmartDiscrete is a discrete device with some added intelligence.These devices can perform additional functions including sensing ofoverstress conditions and reacting to protect themselves or othercircuit elements around them.

The smart features are built into the device during fabrication byusing simple methods to fabricate these additional elements made ofdiodes, zeners and resistors.

Examples of these features are current limiting function, thermalshutdown, short circuit protection, overvoltage protection, automaticrestart and temperature sensing.


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2.42.4 IGBT IGBT Insulated Gate Bipolar TransistorInsulated Gate Bipolar Transistor

The structure is very similar to that of a vertically diffused MOSFET featuring a double diffusion

of a p-type region and an n-type region. An inversion layer can be formed under the gate by

applying the correct voltage to the gate contact as with a MOSFET. The main difference is the use

of a p+ substrate layer for the drain. The effect is to change this into a bipolar device as this p-type

region injects holes into the n-type drift region.


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IGBT CharacteristicsIGBT Characteristics

An IGBT combines the simple gate drive of the Mosfet with

the high current carrying capability of a bipolar transistor.

IGBTs are specially suited for high Voltage and high currentswitching.


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2.52.5 ThyristorsThyristors

A Thyristor or S.C.R. (siliconcontrolled rectifier) is a devicethat can supply large currents orswitch large currents ON or OFF.

Thyristors are specified by thereverse voltage, the gate voltageand current.

A Thyristor acts like a diodepassing current in one directiononly.


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Thyristor OperationThyristor Operation

The thyristor acts as a diode, passing current in one direction only. Thevoltage at the gate controls the flow of current between the anode and the

cathode. When a momentary positive voltage of approximately 2 volts isapplied to the gate, a large current will flow from anode to cathode evenif the voltage at the gate is removed. The thyristor can be turned off byInterrupting the power supply. This can be done using a switch in the +vepower supply rail or bypassing the thyristor anode to cathode with aswitch. Gate current is limited by the use of a series resistor. The thyristoralso needs a load resistor otherwise it may be damaged.


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Thyristor ParametersThyristor Parameters

Parameter Typical Values

On-state Current, IT 0.8 25 A

Peak off-state Voltage, VDRM 30 - 800 V

Peak Surge Current, ITSM 8 - 300 A

Gate Trigger Current, IGT 0.075 30 mA


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What you should knowWhat you should know

You have learnt the basic differences betweendiodes, transistors, Mosfets, Igbt and Thyristors.Consider these as the family names.

You should be able to identify a device andclassify it correctly to its family.

You should remember the different memberswithin each device family.

You should also know some importantcharacteristics about each family and its members.


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How to use this informationHow to use this information

You now have a general background tounderstand the different devices in the

Semiconductor Discrete PortfolioYou should use this material as a reference

Discretes Semiconductors

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