Electronics Technology Fundamentals Chapter 21 Field-Effect Transistors and Circuits.

Slides:



Advertisements
Similar presentations
Electronic Devices Eighth Edition Floyd Chapter 8.
Advertisements

Transistors These are three terminal devices, where the current or voltage at one terminal, the input terminal, controls the flow of current between the.
JUNCTION FIELD EFFECT TRANSISTOR(JFET)
FET ( Field Effect Transistor)
Field Effect Transistor (FET)
Chap. 5 Field-effect transistors (FET) Importance for LSI/VLSI –Low fabrication cost –Small size –Low power consumption Applications –Microprocessors –Memories.
Chapter Five The Field-Effect Transistor. Figure 6—2 A three-terminal nonlinear device that can be controlled by the voltage at the third terminal v.
ELEC 121 ELEC 121 Author unknown whsmsepiphany4.googlepages.com
© 2012 Pearson Education. Upper Saddle River, NJ, All rights reserved. Electronic Devices, 9th edition Thomas L. Floyd Electronic Devices Ninth.
Storey: Electrical & Electronic Systems © Pearson Education Limited 2004 OHT 20.1 Field-Effect Transistors  Introduction  An Overview of Field-Effect.
Field Effect Transistors Topics Covered in Chapter : JFETs and Their Characteristics 30-2: Biasing Techniques for JFETs 30-3: JFET Amplifiers 30-4:
FET ( Field Effect Transistor)
Week 6 – Chapter 3 FET Small-Signal Analysis Mohd Shawal Jadin FKEE UMP © 2009.
Chapter 28 Basic Transistor Theory. 2 Transistor Construction Bipolar Junction Transistor (BJT) –3 layers of doped semiconductor –2 p-n junctions –Layers.
Introduction to FET’s Current Controlled vs Voltage Controlled Devices.
09/16/2010© 2010 NTUST Today Course overview and information.
Chapter 17 Electronics Fundamentals Circuits, Devices and Applications - Floyd © Copyright 2007 Prentice-Hall Chapter 17.
Junction Field Effect Transistor
electronics fundamentals
Field-Effect Transistors
FET ( Field Effect Transistor)
Chapter 5: Field–Effect Transistors
CHAPTER 7 Junction Field-Effect Transistors. OBJECTIVES Describe and Analyze: JFET theory JFETS vs. Bipolars JFET Characteristics JFET Biasing JFET Circuits.
Field Effect Transistor (FET)
Field Effect Transistors By Er. S.GHOSH
Electronic Devices Eighth Edition Floyd Chapter 9.
DMT121 – ELECTRONIC DEVICES
المملكة العربية السعودية وزارة التعليم العالي - جامعة أم القرى كلية الهندسة و العمارة الإسلامية قسم الهندسة الكهربائية ELECTRONIC DEVICES K INGDOM.
FET Amplifiers Chapter 8 Boylestad Electronic Devices and Circuit Theory.
Field Effect Transistor. What is FET FET is abbreviation of Field Effect Transistor. This is a transistor in which current is controlled by voltage only.
Filed Effect Transistor.  In 1945, Shockley had an idea for making a solid state device out of semiconductors.  He reasoned that a strong electrical.
Acknowledged to: Shahrul Ashikin Azmi (PPKSE). Objectives  Explain the operation and characteristics of junction field effect transistors (JFET).  Understand.
Field-Effect Transistors (FETs)
Field Effect Transistors
Robert Boylestad Digital Electronics Copyright ©2002 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Chapter 9: FET.
Chapter 7: FET Biasing.
© 2000 Prentice Hall Inc. Figure 5.1 n-Channel enhancement MOSFET showing channel length L and channel width W.
Depletion-type MOSFET bias circuits are similar to JFETs. The only difference is that the depletion-Type MOSFETs can operate with positive values of V.
MALVINO Electronic PRINCIPLES SIXTH EDITION.
CHAPTER 6 Field Effect Transistors (FETs)
CHAP3: MOS Field-Effect Transistors (MOSFETs)
ANALOGUE ELECTRONICS CIRCUITS 1
Junction Field Effect Transistor
1 DMT 121 – ELECTRONIC DEVICES CHAPTER 5: FIELD-EFFECT TRANSISTOR (FET)
Small-Signal FET Amplifier. FET Small-Signal Model FET amplifiers are similar to BJT amplifiers in operation.The purpose of the amplifier is the same.
Chapter 8: FET Amplifiers. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Electronic Devices and.
SMALL SIGNAL FET (Field– Effect Transistors) AMPLIFIER 1.Introduction/Basic 2.FET Small-Signal Model 3.Fixed-Bias Configuration 4.Self-Bias Configuration.
CHAPTER 5 FIELD EFFECT TRANSISTORS(part a) (FETs).
Field-effect transistors ( FETs) MD.MASOOD AHMAD ASST.PROF ECE DEPT.
Field Effect Transistors
FET FET’s (Field – Effect Transistors) are much like BJT’s (Bipolar Junction Transistors). Similarities: • Amplifiers • Switching devices • Impedance matching.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. MALVINO & BATES SEVENTH EDITION Electronic PRINCIPLES.
course Name: Semiconductors
TRANSISTORS AND THYRISTORS
COURSE NAME: SEMICONDUCTORS Course Code: PHYS 473 Week No. 9.
SILVER OAK COLLEGE OF ENGG. & TECHNOLOGY  SUB – Electronics devices & Circuits  Topic- JFET  Student name – Kirmani Sehrish  Enroll. No
CHAPTER 6 Field Effect Transistors (FETs)
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. MALVINO & BATES SEVENTH EDITION Electronic PRINCIPLES.
CHAPTER 4 :JFET Junction Field Effect Transistor.
Electronics Technology Fundamentals Chapter 19 Bipolar Junction Transistor Operation and Biasing.
FET ( Field Effect Transistor) 1.Unipolar device i. e. operation depends on only one type of charge carriers (h or e) 2.Voltage controlled.
JFET &MOSFET PREPARED BY  JAYSWAL JAYDEEP ( )  GOHIL DARSHAN ( )  PARMAR NARESH ( )  THAKOR MAHESH ( )
Chapter 6 Field effect transistor Ir. Dr. Rosemizi Abd Rahim 1 Ref: Electronic Devices and Circuit Theory, 10/e, Robert L. Boylestad and Louis Nashelsky.
MAHATMA PHULE A.S.C. COLLEGE, PANVEL Field Effect Transistor
The JUNCTION FIELF EFFECT TRANSISTOR (JFET) n channel JFET
ChapTer FiVE FIELD EFFECT TRANSISTORS (FETs)
MOSFET POWERPOINT PRESENTATION BY:- POONAM SHARMA LECTURER ELECTRICAL
LECTURE # 8 FIELD EFFECT TRANSISTOR (FET)
9 Transistor Fundamentals.
JFET Junction Field Effect Transistor.
Presentation transcript:

Electronics Technology Fundamentals Chapter 21 Field-Effect Transistors and Circuits

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to JFETs – P1 Field-Effect Transistor Voltage-controlled device Two basic types Junction FET (JFET) Metal-Oxide Semiconductor FET (MOSFET) Insert Figure 21.1

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to JFETs – P2 Field-Effect Transistor (Continued) Terminals can be viewed like the BJT Source – counterpart of the BJT emitter Drain – counterpart of the BJT collector Gate – counterpart of the BJT base Insert Figure 21.2

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to JFETs – P3 Field-Effect Transistor (Continued) N-Channel JFETs – normally require positive supply voltages P-Channel JFETs – normally require negative supply voltages Insert Figure 21.3

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to JFETs – P4 Operation Overview – the JFET drain current is controlled by varying the channel width with V GS and V DS V GS varies the depletion layer which changes channel width Insert Figure 21.4

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to JFETs – P5 Operation Overview (Continued) V DS also varies the depletion layer Figure 21.5

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to JFETs – P6 Pinch-Off Voltage (V P ) – the value of V DS where further increases in V DS are offset by proportional increases in channel resistance

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to JFETs – P7 Pinch-Off Voltage (V P ) (Continued) Ohmic Region – the portion of the drain curve to the left of V P Constant-Current Region – the region of operation between V P and the breakdown voltage (V BR )

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to JFETs – P8 Shorted-Gate Drain Current (I DSS ) The maximum value of I D Measured under the following conditions: I DSS can be viewed as being the JFET equivalent of I C(sat) for a BJT

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to JFETs – P9 Gate-Source Cutoff Voltage (V GS(off) ) The value of VGS that causes I D to drop to approximately zero V GS(off) always has the same magnitude as V P. For example: If V GS(off) = -8 V, then V P = 8 V

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to JFETs – P10 JFET Biasing Gate-Source Junction Never allowed to become forward biased or gate current may destroy the component Reverse bias causes JFET to have extremely high gate impedance, typically in the high megohm (M  ) range

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to JFETs – P11 Component Control – JFET drain current is controlled by its gate-source voltage where I DSS = the shorted-gate drain current rating of the device V GS = the gate-source voltage V GS(off) = the gate-source cutoff voltage

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to JFETs – P12 Transconductance Curves – represents every possible combination of V GS and I D for the device Example: V GS(off) = -6 V and I DSS = 3 mA

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to JFETs – P13

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Biasing Circuits – P1 Gate Bias – the JFET counterpart of base bias

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Biasing Circuits – P2 Gate Bias (Continued) Does not provide a stable Q-point from one JFET to another Used primarily in switching applications

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Biasing Circuits – P3 Self-Bias – a more viable type of JFET biasing

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Biasing Circuits – P4 Self-Bias (Continued) – graphical procedure for finding I D Plot the minimum and maximum transconductance curves Choose any value of V GS, and determine the corresponding value of I D using: Plot the (V GS, I D ) point and draw a line from this point to the graph origin The points of intersection define the limits of the Q-point operation of the circuit

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Biasing Circuits – P5 Self-Bias (Continued) Example: V GS(off) = -2 V to -8 V, I DSS = 4 mA to 16 mA, and choose V GS = -4 V

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Biasing Circuits – P6 Voltage-Divider Bias

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Biasing Circuits – P7 Voltage-Divider Bias (Continued) – graphical procedure for finding I D Plot the transconductance curves Calculate V G Plot V G on the positive x-axis Calculate I D at V GS = 0 V using: Plot I D on the y-axis Draw a line from the V G point through the point on the y-axis and both curves The points of where the line intersects the JFET curves define the limits of I DQ

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Biasing Circuits – P8 Voltage-Divider Bias (Continued) – Example: V GS(off) = -2 V to -8 V, I DSS = 4 mA to 16 mA Insert Figure 21.19

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Biasing Circuits – P9 Voltage-Divider Bias (Continued) – provides a much more stable Q-point than either gate bias or self-bias

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Biasing Circuits – P10

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Common-Source Amplifiers – P1 Common-Source (CS) Amplifier – the JFET counterpart of the BJT common-emitter amplifier

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Common-Source Amplifiers – P2 Operation Overview

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Common-Source Amplifiers – P3 Transconductance – a ratio of a change in drain current to a change in gate-source voltage where g m = the transconductance of the JFET at a given value of V GS – measured in microsiemens (  S) or micromhos (  mhos)  I D = the change in drain current  V GS = the gate-source cutoff voltage

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Common-Source Amplifiers – P4 Transconductance (Continued) – Example showing variation of g m

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Common-Source Amplifiers – P5 Transconductance (Continued) – the value of g m at a specific value of V GS can be found using: where g m = the value of transconductance at the specific value of V GS g m0 = the maximum value of g m, measured at V GS = 0 V

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Common-Source Amplifiers – P6 Amplifier Voltage Gain – can be relatively unstable because of dependence on g m

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Common-Source Amplifiers – P7 Amplifier Voltage Gain (Continued)

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Common-Source Amplifiers – P8 JFET Swamping – reduces the effects of variations in g m

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Common-Source Amplifiers – P9 JFET Swamping (Continued) – improves stability, but results in a loss of voltage gain

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Common-Source Amplifiers – P10 Amplifier Input Impedance – higher than that of a similar BJT amplifier Gate-Bias and Self-Bias Voltage-Divider Bias

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Common-Drain and Common-Gate Amplifiers – P1 Common-Drain and Common-Gate Amplifiers – the JFET counterparts of the common- collector and common-base BJT amplifiers The Common-Drain Amplifier (Source Follower) – is an amplifier that accepts an input signal at its gate and provides an output signal at its source terminal

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Common-Drain and Common-Gate Amplifiers – P2 The Common-Drain Amplifier (Continued)

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Common-Drain and Common-Gate Amplifiers – P3 The Common-Drain Amplifier (Continued) where

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Common-Drain and Common-Gate Amplifiers – P4 The Common-Drain Amplifier (Continued) Amplifier Input Impedance Voltage-Divider Bias Gate-Bias and Self-Bias

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Common-Drain and Common-Gate Amplifiers – P5 The Common-Drain Amplifier (Continued) Amplifier Output Impedance

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Common-Drain and Common-Gate Amplifiers – P6 The Common-Gate Amplifier – is an amplifier that accepts an input signal at its source terminal and provides an output signal at its drain terminal

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Common-Drain and Common-Gate Amplifiers – P7 The Common-Gate Amplifier (Continued) Input impedance

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Common-Drain and Common-Gate Amplifiers – P8 The Common-Gate Amplifier (Continued) Output impedance

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Common-Drain and Common-Gate Amplifiers – P9 The Common-Gate Amplifier (Continued) Output impedance (Continued) Since r d is typically much larger than R D : where r d =the resistance of the JFET drain y os =the output admittance of the JFET drain

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Common-Drain and Common-Gate Amplifiers – P10

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to MOSFETs: D-MOSFET Operation and Biasing – P1 Metal-Oxide-Semiconductor FET (MOSFET) JFET Drawback – gate must be reverse-biased (depletion-mode operation) MOSFET The input signal can be used to increase the effective size of the channel (enhancement-mode operation) Not restricted to operating with its gate reverse biased

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to MOSFETs: D-MOSFET Operation and Biasing – P2 MOSFET Construction and Handling Depletion-type MOSFETs (D-MOSFETs) - can be operated in both the depletion and enhancement modes  Enhancement-type MOSFETs (E-MOSFETs) – restricted to enhancement-mode operation

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to MOSFETs: D-MOSFET Operation and Biasing – P3 MOSFET Construction and Handling (Continued) Insert Figure 21.36

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to MOSFETs: D-MOSFET Operation and Biasing – P4 MOSFET Construction and Handling (Continued) SiO 2 layer insulating the gate from the channel is very thin and be be destroyed easily by static electricity Many MOSFETs are manufactured with protective diodes Insert Figure 21.37

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to MOSFETs: D-MOSFET Operation and Biasing – P5 MOSFET Construction and Handling (Continued) Precautions if inputs not protected Short leads or store in conductive foam (not Styrofoam) Handle MOSFETs by the case, not the leads Do not install or remove any MOSFET while power is applied. Also, make sure that any signal source is removed before turning supply voltage off or on

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to MOSFETs: D-MOSFET Operation and Biasing – P6 D-MOSFETs Depletion Mode - the characteristics of the D-MOSFET are very similar to those of the JFET Enhancement Mode – I D can be greater than I DSS

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to MOSFETs: D- MOSFET Operation and Biasing – P7 D-MOSFETs (Continued) – uses the same transconductance equation as the JFET

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to MOSFETs: D-MOSFET Operation and Biasing – P8 Transconductance – the value of g m is found in the same way that it is for a JFET

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to MOSFETs: D-MOSFET Operation and Biasing – P9 D-MOSFET Biasing Circuits – same as those used for JFETs

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to MOSFETs: D-MOSFET Operation and Biasing – P10 D-MOSFET Input Impedance Extremely high due to the insulating (SiO 2 ) layer Example: A gate current = 10 pA translates to an input impedance of 3.5 X 

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Introduction to MOSFETs: D-MOSFET Operation and Biasing – P11

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved E-MOSFETs – P1 Enhancement MOSFETs (E-MOSFETs) – conduct only in the enhancement mode

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved E-MOSFETs – P2 Transconductance Curve Threshold Voltage (V GS(th) ) – the minimum positive voltage at which the device turns on Insert Figure 21.43

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved E-MOSFETs – P3 Calculating I D where k is a constant for the MOSFET, found as: where I D(on) and V GS(on) are obtained from a spec sheet

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved E-MOSFETs – P4 E-MOSFET Biasing Circuits Voltage-divider and gate-bias can be used with E-MOSFETs Drain-Feedback Bias – MOSFET counterpart to BJT collector- feedback bias

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Complementary MOSFETs: A MOSFET Application – P1 MOSFETs used in digital electronics Use rectangular waveforms Logic levels – dc levels used in digital applications Logic family – group of circuits that have similar operating characteristics Complementary MOS (CMOS) – a logic family Less complex than BJT logic circuits Less supply current than BJT logic circuits Need almost no input current

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Complementary MOSFETs: A MOSFET Application – P2 Complementary MOS (CMOS) (Continued)

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Additional FET Applications – P1 JFET Radio-Frequency (RF) Amplifier

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Additional FET Applications – P2 The Cascode Amplifier

Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved Additional FET Applications – P3 Power MOSFET Driver