ANALOG INTEGRATED CIRCUITS FOR COMMUNICATION Principles, Simulation and Design

ANALOG INTEGRATED CIRCUITS FOR COMMUNICATION Principles, Simulation and Design

ANALOG INTEGRATED CIRCUITS FOR COMMUNICATION Principles, Simulation and Design by Donald 0. Pederson University of California and Kartikeya Mayaram Texas Instruments Springer Science+Business Media, LLC

Library of Congress Cataloging-in-Publication Data Pederson, Donald O. Analog integrated circuits for communication : principles, simulation and design 1 Donald O. Pederson and Kartikeya Mayaram. p. cm. Includes index. ISBN 978-1-4757-2130-0 DOI 10.1007/978-1-4757-2128-7 ISBN 978-1-4757-2128-7 (ebook) 1. Linear integrated circuits. 1. Mayaram, Kartikeya. II. Title. TK7874.P43 1991 621.381 '.S-dc20 90-45448 CIP Copyright 1991 by Springer Science+Business Media New York Originally published by Kluwer Academic Publishers in 1991 Softcover reprint ofthe hardcover 1st edition 1991 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher, Springer Science+Business Media, LLC. Printed on acid-jree paper.

Contents Preface i x Chapter 1 LARGE-SIGNAL PERFORMANCE OF THE BASIC GAIN STAGES IN ANALOG ICs 1 1.1 The Emitter-Coupled Pair 1 1.2 The Large-Signal DC Transfer Characteristic of the ECP 3 1.3 Distortion Generation and Characterization 9 1.4 Large-Signal Circuit Analysis of the ECP 13 1.5 Series Expansions to Obtain Distortion Components 17 1.6 The Source-Coupled Pair 19 1.7 A Series Expansion to Obtain Distortion Components for the SCP ~ Chapter 2 AMPLIFIER POWER SERIES AND DISTORTION 3 1 2.1 General Power Series Description 31 2.2 Common-Emitter Stage Example 34 2.3 The Ideal C-E Stage with a Large Sinusoidal Input Voltage 40 2.4 Power Series and Fourier Series Characterizations 44 2.5 The Common-Source MOS Amplifier Stage 49 2.6 Intermodulation Distortion 55 Chapter 3 DISTORTION GENERATION WITH SOURCE RESISTANCE AND NONLINEAR BETA 6 1 3.1 Linearization of a Bipolar Stage Due to Source Resistance 61 3.2 Distortion Reduction with Source Resistance 66 3.3 The ECP with Source Resistance 72 3.4 Nonlinear Beta and Distortion 77 3.5 Example of Distortion due to Beta(lc) 87 Chapter 4 DISTORTION IN FEEDBACK AMPLIFIERS 8 9 4.1 Effects of Negative Feedback 89 v

vi CONTENTS 4.2 Feedback for a General Amplifier 4.3 AC-E Stage with Shunt Feedback 4.4 The C-E Stage with Emitter Feedback 4.5 Alternative Loop-Gain Calculations 4.6 Emitter Feedback in the ECP 4. 7 Internal Feedback in the ECP and the SCP Chapter 5 BASIC IC OUTPUT STAGES 5.1 Requirements for an Output Stage 5.2 The Emitter Follower 5.3 Distortion Calculation using Differential Error 5.4 Power Conversion Efficiency 5.5 The Source Follower 5.6 Push-Pull Emitter Followers 5.7 The Push-Pull Source Follower 5.8 Push-Pull, Single-Polarity Output Stages Chapter 6 TRANSFORMERS 6.1 Introduction 6.2 Elementary Coupled Coils 6.3 Circuit Model for a Transformer 6.4 Inductive Two-Port Parameters 6.5 A Transformer-Coupled, Class-A BIT Output Stage 6.6 Maximum Power Transfer 6.7 Class-A Push-Pull Operation 6.8 Class AB Operation Chapter 7 TUNED CIRCUITS IN BANDPASS AMPLIFIERS 7.1 Introduction 7.2 The Single-Tuned Circuit 7.3 Lowpass Equivalents 7.4 Transformer-Coupled Single-Tuned Circuits 7.5 Single-Tuned, Bandpass Circuits with Loosely Coupled Transformers 7.6 Double-Tuned Stages 94 103 106 114 116 121 129 129 130 132 144 149 151 163 166 175 175 176 183 185 189 200 201 210 215 215 217 220 223 225 231 Chapter 8 SIMPLE BANDPASS AMPLIFIERS 2 3 7 8.1 Simple Active RC Bandpass Amplifiers 237 8.2 An ECP Bandpass Amplifier 241 8.3 Synchronous Tuning, Cascading, and Bandwidth Shrinkage 249

CONTENTS vii 8.4 Effects of Internal Feedback 253 8.5 Multistage Bandpass Design Example 261 8.6 Cross Modulation 268 Chapter 9 BASIC ELECTRONIC OSCILLATORS 2 7 1 9.1 Instabilities, Oscillations and Oscillators 271 9.2 The Ideal Electronic Oscillator 273 9.3 A Tunnel-Diode Oscillator 275 9.4 The van der Pol Approximation 279 9.5 Tunnel-Diode Oscillator Example 282 9.6 Wien-Type Oscillators 286 9.7 Transformer-Coupled ECP Oscillators 301 9.8 Transformerless ECP Oscillators 310 Chapter 10 ELECTRONIC OSCILLATORS WITH BIAS-SHIFT LIMITING 3 2 3 10.1 Bias Shift during Oscillator Buildup in an ECP Oscillator 323 10.2 The Basic Oscillator Equation 327 10.3 Single-Device, Transformer-Coupled Oscillators 333 10.4 Bias Shift and Harmonic Balance 337 10.5 Transformer-Coupled MOS Oscillators 346 10.6 Squegging 349 10.7 Phase-Shift Oscillators 355 10.8 The Colpitt's Oscillator 358 10.9 Crystal-Controlled Oscillators 365 Chapter 11 RELAXATION AND VOLTAGE-CONTROLLED OSCILLATORS 3 6 9 11.1 Relaxation-Mode Oscillations 369 11.2 Oscillator Graphical Analysis 373 11.3 Regenerative Switching in a Relaxation Oscillator 379 11.4 Recovery Analysis in a BJT Relaxation Feedback Oscillator 384 11.5 Other Astable Oscillators 390 11.6 A CMOS Relaxation Oscillator 393 11.7 Voltage- and Current -Controlled Oscillators 396 11.8 An Astable Schmitt Circuit 400 11.9 Equivalence of the Schmitt and Loop-Coupled Bistable Circuits 402 11.10 A BJT VCO 405 Chapter 12 ANALOG MULTIPLIERS, MIXERS AND MODULATORS 41 3 12.1 The Emitter-Coupled Pair as a Simple Analog Multiplier 413

viii CONTENTS 12.2 A Subtraction Improvement 12.3 Predistortion and Linearity Improvement in the ECP 12.4 The Gilbert Cell 12.5 MOS Analog Multipliers 12.6 Mixing, Modulation and Frequency Translation 12.7 The Fully Balanced (Quad) Mixer 12.8 Single-Device BIT Mixers 12.9 FET Mixers 12.10 Modulators Chapter 13 DEMODULATORS AND DETECTORS 13.1 AM Demodulation using Analog Multipliers 13.2 Synchronous AM Detection 13.3 Peak Detectors 13.4 Automatic Gain Control 13.5 FM Demodulation, Off-Peak Detection 13.6 Discriminators 13.7 FM Demodulators using Multipliers Chapter 14 PHASE-LOCKED LOOPS 14.1 Basic Configurations and Applications 14.2 A Simple Circuit Model of a PLL 14.3 The Small-Signal Analysis of the PLL 14.4 Dynamics of the PLL in Locked Condition 14.5 The Lock and Capture Ranges 14.6 PLLs with Overdriven PCs and Relaxation Oscillators 14.7 PLL Design Example 14.8 PLL Parameters for a Typical IC Realization 14.9 A PLL Example with a FM input Chapter 15 RECTIAERS,REGULATORSANDVOLTAGEREFERENCES 15.1 Simple Half-Wave Rectifiers 15.2 Full-Wave and Bridge Rectifiers 15.3 Series Regulators 15.4 An Introduction to Switching Regulators 15.5 IC Voltage References Problems Index 418 422 425 431 434 435 439 443 449 451 451 455 457 466 469 474 476 479 479 483 488 493 501 508 512 513 516 521 521 527 527 534 542 549 565

Preface This book deals with the analysis and design of analog integrated circuits that form the basis of present-day communication systems. The material is intended to be a textbook for class use but should also be a valuable source of information for a practicing engineer. Both bipolar and MOS transistor circuits are analyzed and many numerical examples are used to illustrate the analysis and design techniques developed in this book. A set of problems is presented at the end of the book which covers the subject matter of the whole book. The book has originated out of a senior-level course on nonlinear, analog integrated circuits at the University of California at Berkeley. The material contained in this book has been taught by the first author for several years and the book has been class tested for six semesters. This along with feedback from the students is reflected in the organization and writing of the text. We expect that the students have had an introductory course in analog circuits so that they are familiar with some of the basic analysis techniques and also with the operating principles of the various semiconductor devices. Several important, basic circuits and concepts are reviewed as the subject matter is developed. The approach taken is as follows: first-order analysis techniques are developed first using basic principles and simple device models. Then circuit simulation is used to corroborate the analysis techniques. This procedure provides insight into the operation of circuits and a systematic way of getting an initial design of a circuit. The circuit simulation program SPICE has been extensively used to verify the results of first-order analyses, and for detailed simulations with complex device models. In this manner the student can appreciate the shortcomings of the hand analysis and can resort to simulations when necessary. Simulation results can only be interpreted ix

X PREFACE once one has an understanding of how a circuit operates and this is reflected by the manner in which the material is presented. SPICE input files are given for all the circuits that have been analyzed so that the students can quickly duplicate the input file and verify the results. The material contained in this book is covered in a 15-week semester course at the University of California at Berkeley. A chapter-by-chapter summary of the topics covered is given below. Chapter 1 considers the large-signal performance of emitter-coupled pair and source-coupled pair circuits. The concept of harmonic distortion is introduced and series expansions are used as a method for obtaining the distortion components and the results are verified with SPICE simulations. Another technique is introduced in Chapter 2 for computing the distortion components. The transfer characteristic of an amplifier is described by a power series and the harmonic distortion factors are derived. The concept of intermodulation distortion is also developed. In Chapter 3 the distortion modification/generation due to source resistance and nonlinear beta in bipolar transistor circuits is considered. Chapter 4 describes how distortion is modified in feedback amplifiers. The concept of feedback is reviewed and applied to several example circuits with particular attention to establishing correctly the appropriate loop-gain value. Distortion and power transfer calculations in the basic IC output stages are the concern in Chapter 5. Class A, Class B, and Class AB output stages are described. An alternate method for distortion calculation is also presented. Chapter 6 deals with transformers which are essential components in many baseband output stages and which also form the basis for tuned circuits and bandpass amplifiers. The basic low-frequency transformer is developed together with the circuit models and parameters which describe its electrical performance. In this chapter the analysis of transformer-coupled amplifiers and output stages is provided. Tuned circuits are reviewed in Chapter 7. Elementary circuits and evaluation techniques are introduced. Major emphasis is given to circuits employing inductive transformers. The design of simple bandpass amplifiers is considered in Chapter 8. Synchronous tuning, cascading, and bandwidth shrinkage are described and applied to the design of a multistage bandpass amplifier. The concept of cross modulation is also introduced. Chapter 9 describes basic electronic oscillators. Simple and special circuits are used as a basis to provide insight into the design of oscillator circuits. The development is based both on the negative-resistance approach to oscillator analysis as well as the feedback approach.

PREFACE xi The concept of bias-shift limiting is introduced in Chapter 10. Steadystate operation of the oscillator corresponds to Class C operation. Single device bipolar and MOS circuits are described. Chapter 11 deals with relaxation and voltage-controlled oscillators. A graphical analysis of the basic oscillator is used to develop ideas that are helpful in understanding the operation and the design of these oscillators. Relaxation oscillator examples in both BJT and MOS technologies are presented and techniques for controlling the period of oscillation are also described leading to voltage (current) controlled oscillators. Analog multipliers, mixers, and modulators are considered in Chapter 12. The emitter-coupled pair is first introduced as a simple analog multiplier and extended to explain the development and operation of a. fourquadrant multiplier. The concepts of mixing and modulation are developed and various examples are given. Chapter 13 deals with demodulators and detectors which form an integral part of any communication circuit. Various techniques for AM and FM demodulation are described. Phase-locked loops which are extensively used as frequency synthesizers and demodulators are examined in Chapter 14. The basic operation of a phase-locked loop is described using macromodels suitable for SPICE simulations. Chapter 15 describes rectifier, regulator, and voltage-reference circuits. Simple rectifier circuits are introduced. The concept of regulation is developed and series and switching regulators are described. The regulator circuits use voltage references and some basic reference circuits are presented. We are pleased to acknowledge the many comments and suggestions provided by our colleagues and students, especially Professor R. G. Meyer. We also appreciate the contributions of Ms. Elizabeth Rhine, Ms. Susie Reynolds, and Ms. Gwyn Horn for their excellent formatting and compositing of the manuscript. Donald 0. Pederson Kartikeya Mayaram

ANALOG INTEGRATED CIRCUITS FOR COMMUNICATION Principles, Simulation and Design