Feedback Amplifiers Theory and Design

279 Pages·2004·7.15 MB·English

FEEDBACK AMPLIFIERS
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Feedback Amplifiers
Theory and Design
by
Gaetano Palumbo
University of Catania
and
Salvatore Pennisi
University of Catania
KLUWER ACADEMIC PUBLISHERS
NEW YORK,BOSTON, DORDRECHT, LONDON, MOSCOW
eBookISBN: 0-306-48042-5
Print ISBN: 0-7923-7643-9
©2003 Kluwer Academic Publishers
NewYork, Boston, Dordrecht, London, Moscow
Print ©2002 Kluwer Academic Publishers
Dordrecht
All rights reserved
No part of this eBook maybe reproducedor transmitted inanyform or byanymeans,electronic,
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Created in the United States of America
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To our families:
Michela and Francesca
Stefania, Francesco, and Valeria
CONTENTS
ACKNOWLEDGEMENTS xi
PREFACE xiii
1. INTRODUCTION TO DEVICE MODELING 1
(byGianluca Giustolisi)
1.1 DOPED SILICON 1
1.2 DIODES 2
1.2.1 Reverse Bias Condition 5
1.2.2 Graded Junctions 6
1.2.3 Forward Bias Condition 7
1.2.4 Diode Small Signal Model 9
1.3 MOS TRANSISTORS 9
1.3.1 Basic Operation 10
1.3.2 Triode orLinearRegion 12
1.3.3 Saturation orActive Region 14
1.3.4 Body Effect 15
1.3.5 p-channel Transistors 16
1.3.6 Saturation Region Small Signal Model 16
1.3.7 Triode Region SmallSignalModel 21
1.3.8 Cutoff Region Small Signal Model 23
1.3.9 Second Order Effects in MOSFET Modeling 24
1.3.10Sub-threshold Region 28
1.4 BIPOLAR-JUNCTIONTRANSISTORS 29
1.4.1 Basic Operation 31
1.4.2 Early Effect or Base Width Modulation 32
1.4.3 Saturation Region 33
1.4.4 Charge Stored in theActive Region 33
1.4.5 Active Region Small Signal Model 34
REFERENCES 36
2. SINGLE TRANSISTOR CONFIGURATIONS 37
2.1 THE GENERIC ACTIVE COMPONENT 37
2.2 AC SCHEMATICDIAGRAM ANDLINEARANALYSIS 39
2.3 COMMON X (EMITTER/SOURCE) CONFIGURATION 41
2.4 COMMON XWITH DEGENERATIVERESISTANCE 42
2.5 COMMON Y(BASE/GATE) 48
2.6 COMMON Z(COLLECTOR/DRAIN) 51
2.7 FREQUENCY RESPONSE OF SINGLE TRANSISTOR 54
CONFIGURATIONS
viii
2.7.1 Common XConfiguration 55
2.7.2 Common Xwith a Degenerative Resistance 56
2.7.3 Common YandCommon ZConfigurations 61
3.FEEDBACK 63
3.1 METHOD OFANALYSIS OFFEEDBACKCIRCUITS 64
3.2 SIGNALFLOWGRAPH ANALYSIS 67
3.3 THE ROSENSTARK METHOD 69
3.4 THE CHOMA METHOD 72
3.5 THE BLACKMANTHEOREM 74
4. STABILITY - FREQUENCY AND STEP RESPONSE 77
4.1 ONE-POLEFEEDBACKAMPLIFIERS 78
4.2 TWO-POLEFEEDBACKAMPLIFIERS 82
4.3 TWO-POLE FEEDBACK AMPLIFIERS WITH A POLE- 92
ZERO DOUBLET
4.4 THREE-POLE FEEDBACK AMPLIFIERS WITH REAL 97
POLES
4.5 THREE-POLEFEEDBACKAMPLIFIERS WITH A PAIROF 98
COMPLEXAND CONJUGATEPOLES
4.6 TWO-POLEFEEDBACK AMPLIFIERSWITHAZERO 100
5. FREQUENCY COMPENSATION TECHNIQUES 103
5.1 DOMINANT-POLECOMPENSATION 104
5.2 MILLER (POLE-SPLITTING)COMPENSATION 106
5.3 COMPENSATION OFTHEMILLER RHPZERO 109
5.3.1 Nulling Resistor 110
5.3.2 Voltage Buffer 111
5.3.3 Current Buffer 114
5.4 NESTED MILLERCOMPENSATION 116
5.4.1 General Features 116
5.4.2 RHP Cancellation withNullingResistors 120
5.5 REVERSED NESTEDMILLER COMPENSATION 126
5.5.1 General Features 126
5.5.2 RHP Cancellation withNullingResistors 130
5.5.3 RHP Cancellation with One Real Voltage Buffer 131
5.5.4 RHP Cancellation with OneRealCurrentBuffer 134
6.FUNDAMENTAL FEEDBACKCONFIGURATIONS 137
6.1 SERIES-SHUNT AMPLIFIER 137
6.1.1 Series-shunt Amplifier with Buffer 146
6.2 SHUNT-SERIESAMPLIFIER 148
6.3 SHUNT-SHUNT AMPLIFIER 155
ix
6.4 SERIES-SERIES AMPLIFIER 158
6.5 A GENERAL VIEW OF SINGLE-LOOP AMPLIFIERS 162
6.6 FREQUENCY COMPENSATION OF THE FUNDAMENTAL 165
CONFIGURATIONS
6.6.1 Frequency Compensation of the Series-Shunt Amplifier 166
6.6.2 Frequency Compensation of the Shunt-Series Amplifier 169
6.6.3 Frequency Compensation of the Shunt- Shunt Amplifier 171
6.6.4 Frequency Compensation of the Series-Series Amplifier 172
7.HARMONIC DISTORTION 173
7.1 HARMONIC DISTORTION AT LOW FREQUENCY 176
7.1.1Nonlinear Amplifier with Linear Feedback 176
7.1.2Nonlinear Amplifier with Nonlinear Feedback 178
7.2 HARMONIC DISTORTION IN THE FREQUENCY DOMAIN 182
7.2.1Open-loop Amplifiers 182
7.2.2Closed-loop Amplifiers 185
7.3 HARMONIC DISTORTION AND COMPENSATION 191
7.3.1 Two-stage Amplifier with Dominant-Pole Compensation 191
7.3.2 Two-stage Amplifier with Miller Compensation 193
7.3.3Single-stage Amplifiers 199
7.4 AN ALTERNATIVE FREQUENCY ANALYSIS 205
8.NOISE 207
8.1 BASIC CONCEPTS 207
8.2 EQUIVALENT INPUT NOISE GENERATORS 209
8.3 NOISE MODELS OF CIRCUIT COMPONENTS 212
8.4 EFFECT OF FEEDBACK 214
9. EXAMPLES OF FEEDBACK IN INTEGRATED CIRCUITS 221
9.1 THE OUTPUT RESISTANCE OF A DIFFERENTIAL 221
AMPLIFIER WITH CURRENT-MIRROR LOAD
9.2 THE WILSON CURRENT MIRROR 224
9.3 THE CASCODE CURRENT MIRROR 228
9.4 THE CURRENT FEEDBACK OPERATIONAL AMPLIFIER 229
AND ITS HIGH-LEVEL CHARACTERISTICS
9.5 TRANSISTOR-LEVEL ARCHITECTURE, SMALL-SIGNAL 232
MODEL, AND FREQUENCY COMPENSATION OF CFOAS
9.6 INTEGRATORS AND DIFFERENTIATORS WITH CFOAS 236
9.7 CFOA VERSUS VOA 238
x
APPENDIX: FREQUENCYANALYSISOFRCNETWORKS 243
A.1 TRANSFERFUNCTIONOFAGENERIC RCNETWORK 243
A.2APPROXIMATED POLES 247
REFERENCES 251
ABOUT THE AUTHORS 263