HIGHLY LINEAR INTEGRATED WIDEBAND AMPLIFIERS. Design and Analysis Techniques for Frequencies from Audio to RF

Transcription

1 HIGHLY LINEAR INTEGRATED WIDEBAND AMPLIFIERS Design and Analysis Techniques for Frequencies from Audio to RF

2 THE KLUWER INTERNATIONAL SERIES IN ENGINEERING AND COMPUTER SCIENCE ANALOG CIRCUITS AND SIGNAL PROCESSING Consulting Editor: Mohammed Ismail. Ohio State University Related Titles: DYNAMIC TRANSLINEAR AND LOG DOMAIN CIRCUITS: Analysis and Synthesis, Jan Mulder, Wouter A. Serdijn, Albert C. van der Woerd, Arthur H. M. van Roermund; ISBN: DISTORTION ANALYSIS OF ANALOG INTEGRATED CIRCUITS, Piet Wambacq, Willy Sansen; ISBN: NEUROMORPIUC SYSTEMS ENGINEERING: Neural Networks in Silicon, edited by Tor Sverre Lande; ISBN: DESIGN OF MODULATORS FOR OVERSAMPLED CONVERTERS, Feng Wang, Ramesh Harjani, ISBN: SYMBOLICANALYSIS IN ANALOG INTEGRATEDCIRCUITDESIGN, Henrik Floberg, ISBN: SWITCHED CURRENT DESIGN AND IMPLEMENTATION OF OVERSAMPLING AID CONVERTERS, Nianxiong Tan, ISBN: CMOS WIRELESS TRANSCEIVER DESIGN, Jan Crots, Michiel Steyaert, ISBN: DESIGN OF LOW VOLTAGE, LOW POWER OPERATIONAL AMPLIFIER CELLS, Ron Hogervorst, Johan H. Huijsing, ISBN: VLSI COMPATIBLE IMPLEMENTATIONS FOR ARTIFICIAL NEURAL NETWORKS, Sied Mehdi Fakhraie, Kenneth Carless Smith, ISBN: CHARACTERIZATION METHODS FOR SUBMICRON MOSFETs, edited by Hisham Haddara, ISBN: LOW VOLTAGE LOW POWER ANALOG INTEGRATED CIRCUITS, edited by Wouter Serdijn, ISBN: INTEGRATED VIDEO.FREQUENCY CONTINUOUS TIME FILTERS: High Performance Realizations in BiCMOS, Scott D. Willingham, Ken Martin, ISBN: FEED FORWARD NEURALNETWORKS: Vector DecomposiJion Analysis, Modellingand Analog Implementation, Anne-Johan Annema, ISBN: FREQUENCY COMPENSATION TECHNIQUES LOW POWER OPERATIONAL AMPLIFIERS, Ruud Easchauzier, Johan Huijsing, ISBN: ANALOG SIGNAL GENERATION FOR BIST OF MIXED SIGNAL INTEGRATED CIRCUITS, Gordon W. Roberts, Albert K. Lu, ISBN: INTEGRATED FIBER OPTIC RECEIVERS, Aaron Buchwald, Kenneth W Martin, ISBN: MODELING WITH AN ANALOG HARDWARE DESCRIPTION LANGUAGE, H. Alan Mantooth,Mike Fiegenbaum, ISBN: LOW VOLTAGE CMOS OPERATIONAL AMPLIFIERS: Theory, Design and Implementation, Satoshi Sakurai, Mohammed Ismail, ISBN: ANALYSIS AND SYNTHESIS OF MOS TRANSLINEAR CIRCUITS, Remco J. Wiegerink, ISBN: COMPUTER AIDED DESIGN OF ANALOG CIRCUITS AND SYSTEMS, L Richard Carley, Ronald S. Gyurcsik, ISBN: IUGH PERFORMANCE CMOS CONTINUOUS-TIME FILTERS, Jose Silva-Martfnez, Michiel Steyaert, Willy Sansen, ISBN: SYMBOLIC ANALYSIS OF ANALOG CIRCUITS: Techniques and Applications, Lawrence P. Huelsman, Georges G. E. Gielen, ISBN: DESIGN OF LOW VOLTAGE BIPOLAR OPERATIONAL AMPLIFIERS, M. Jeroen Fonderie, Johan H. Huijsing, ISBN: STATISTICAL MODELING FOR COMPUTER AIDED DESIGN OF MOS VLSI CIRCUITS, Christopher Michael, Mohammed Ismail, ISBN: X

3 HIGHLY LINEAR INTEGRATED WIDEBAND AMPLIFIERS Design and Analysis Techniques for Frequencies from Audio to RF by Henrik SjOland Lund University, Sweden ~. " SPRINGER SCIENCE+BUSINESS MEDIA, LLC

4 Library of Congress Cataloging-in-Publication Data Sjliland, Henrik, Highly linear integrated wideband amplifiers : design and analysis techniques for frequencies from audio to RF / by Henrik Sjoland. p. cm. -- (The Kluwer international series in engineering and computer science ; SECS 490) Includes bibliographical references and index. ISBN ISBN (ebook) DOI / Broadband amplifiers--design and construction. 2. Linear integrated circuits. 3. Power amplifiers. 1. Title. II. Series. TK B74S '35--dc CIP Copyright 1999 Springer Science+Business Media New York Origina11y published by Kluwer Academic Publishers, New York in 1999 Softcover reprint ofthe hardcover Ist edition 1999 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-free paper.

5 Contents List offigures ix Preface xiii Acknowledgements xv 1 Introduction Wideband IF Amplifiers RF Power Amplifiers Audio Power Amplifiers References 8 2 Integrated Transistors and Amplifiers Integrated Analog Electronics in Short Amplifiers in General.. ll 2.3 Transistors MOS Transistors Small Signal Model Dynamic Effects and Noise Short Channel Effects Bipolar Transistors References 24 3 Amplifier Linearization Techniques Negative Feedback Feed-Forward Predistortion Cancellation References 33

6 Contents 4 Advanced Feedback Techniques The Asymptotic-Gain Model Stability Phase-Compensation Techniques Feedback Boosting The Topology Analysis Detailed Stability Analysis Experiment and Simulations Other Topologies Distortion Cancellation at Signal Frequencies References 50 5 Output Stages Classes ofoperation Low Voltage Output Stages CMOS Output Stages Bipolar Output Stages References 62 6 Analysis and Measurement ofdistortion Computer Simulation of Distortion Distortion Measurement Intermodulation Distortion related to THD Models of the Nonlinear Amplifier Input Signals Static Distortion Static Clipping Static Distortion Before Clipping Dynamic Distortion Slew-Rate Clipping Dynamic Distortion Before Clipping The Method Example Numerical Experiments Static Nonlinearity Only Both Dynamic and Static Nonlinearity References 85

7 Contents 7 Audio Power Amplifiers Requirements of Audio Power Amplifiers General Requirements Special Requirements ofintegrated Battery-Pow Class of Operation Class AB Class S CMOS vs. Bipolar Two CMOS Class AB Designs Output Stages Output Stage with Blomley Topology A Low Voltage Output Stage Phase-Compensation Phase-Compensation of the Blomley Phase-Compensation ofthe Low Voltage InputStages l0l Blomley Amplifier Input Stage Low Voltage Input Stage Simulation and Measurement Results The Blomley Amplifier Results The Low Voltage Amplifier Results Layout and Chip Photos References Wideband IF Amplifiers Performance Requirements The Topology Output Stages CMOS OutputStages Bipolar Output Stage Input Stages CMOS Input Stage Bipolar Input Stage Middle Stage Common-Mode Feedback Simulations and Measurements Schematics Results Chip Photos References 128

8 Contents 9 Inductorless RF CMOS Power Amplifiers Requirements on RF Power Amplifiers CMOS RF Power Amplifiers using Inductors An Inductorless CMOS RF Power Amplifier Amplifier Topology Output Stage Driver Stage Input Stage Simulations and Measurement Results Conclusions Layout and Chip Photo References Layout Aspects Passive Devices Resistors Capacitors Inductors Active Devices MOS Transistors The Layers and Their Physical Corresp Layout for Low Noise Layout for High Speed Layout Techniques for Wide Transistors High Current Layout Bipolar Transistors Matching of Transistors References 159 Index 161

9 List offigures 1.1 The receiver side of a conventional base station Base station with wideband IF amplifier Example ofchannels with different power Spectral widening disturbing adjacent channels The output spectrum when the input is (a) a sinusoid The intercept diagram showing 3rd orderintercept and compress Enhancement MOS transistor symbols (a) N (b) P Simple small signal schematic of an MOS transistor Velocity saturation Effect of velocity saturation on/r Symbols for bipolar transistors (a) npn (b) pnp A simple small-signal equivalent circuit of a bipolar transistor The elementary feedback model Basic feed-forward configuration Feed-forward configuration with compensation for time-delays (a) The principle of predistortion (b) An MOS current mirror Predistortion based on model amplifier (a) The principle ofcancellation (b) A CMOS inverter (a) Example of Nyquist diagram. (b) Enlarged view around Example of Bode diagram. (a) Asymptotic (b) With gain and Illustration of different phase-compensation methods A three stage amplifier topology with double nested Miller The basic inverting topology The complete inverting topology The boost in the feedback (extra loop gain) Measured THD with and without feedback boosting Simulated THD with and without feedback boosting (a) A non-inverting topology (b) A floating negative resistance The tail currents of the output stage The tail currents vs. lout for different classes of operation Maximum efficiency for class B and push-pull class A vs. amplit The connection of the output devices in a low voltage output stage Example of ultimate low voltage push-pull output stage with Example of low voltage topology with complementary amplifiers Connection of the output devices in a low voltage bipolar amplifier Example of low voltage bipolar output stage 60

10 List of Figures 5.9 Connection ofoutput devices in an npn-only bipolar process Example ofnpn-only push-pull stage Static characteristic The probability density function ofa sinusoid with amplitude A The probability density function ofthe Gaussian wideband signal The spectral density of the wideband signal THDIIM vs. A/C7 and n THDIIM vs. A and n when A/C7= Slew-rate clipping scenario Amplifier model for the numerical experiment A simplified schematic ofa class S output stage The Blomley topology Schematic of the Blomley output stage The basic topology of the low voltage output stage Different methods to establish VB2 and VB Simplified frequency responses of (a) the output stage The local feedback network ofthe output stage The demanded gain and the open-loop gain of the output stage The output stage with reversed nested Miller compensation Voltage gain A and feedback factor f3 ofthe output stage The input stage of the Blomley amplifier The frequency response of the input stage The low voltage input stage Total schematic of the power amplifier with Blomley topology Total schematic ofthe low voltage audio power amplifier THD at 1kHz 80 vs output amplitude and supply voltage THD vs. frequency at IVpp in 80 and 1.5V supply Micrograph ofthe 80 amplifier with Blomley topology Micrograph of the 1.5V audio power amplifier Topology of the wideband IF amplifiers The CMOS output stage The CMOS output stage including bias circuit The bipolar output stage The CMOS input stage Two different bipolar input stages CMOS and bipolar middle stage CMOS common-mode feedback circuit Bipolar common-mode feedback circuit The entire CMOS schematic with device parameters The entire bipolar schematic with parameters Microphotograph of the CMOS wideband IF amplifier Microphotograph of the bipolar wideband IF amplifier 127

11 List offigures 9.1 Topology ofthe inductorless CMOS RF power amplifier Simplified schematic of the output stage The 3rd order harmonic distortion vs. VgsejfO and Your The driver stage The total schematic with device parameters Simulated frequency response Measured frequency response Measured intercept diagrams Measured power added efficiency (PAE) Microphotograph of the RF power amplifier Example of resistor layout Layout of two matched resistors Simple model of resistor with parasitic capacitance Layout of two matched capacitors Simple model ofcapacitor with parasitics Layout of an integrated inductor Simple NMOS transistor layout and the corresponding cross-se Example of finger layout Example of waffle-iron layout High current MOS transistor in a process with two metal layers 158

12 Preface This book deals with techniques for designing integrated wideband amplifiers with high linearity. It is intended for professional designers of integrated amplifiers and graduate students in this field. Amplifiers with operating frequencies from Audio to RF are covered. This book is based on my Ph.D. thesis, which was published in November The aim ofthe project, supervised by professor Sven Mattisson, was to design integrated wideband amplifiers with high linearity for different applications. In the book an enhanced feedback configuration called feedback boosting is described. It is capable ofvery low distortion. Theoretically a complete distortion cancellation can be achieved. Also described is a statistical method for relating the intermodulation distortion ofa wideband signal to the total harmonic distortion (THO) of a single tone. The motivation for this is that the THO, as opposed to the intermodulation distortion, is easy to measure and use as a design parameter. This method can handle both static and dynamic nonlinearities. High-performance amplifier designs are also presented, complete with measurement results and chip photos. The different designs cover operating frequencies from audio to RF. Two fully integrated CMOS class AB power amplifiers are described. They are capable ofdirectly driving an 80 loudspeaker. One of the amplifiers can also operate on a supply voltage as low as 1.SY. Two wideband amplifiers are also presented, one in CMOS and one bipolar. They have high linearity from DC to 20MHz. Finally, a fully integrated CMOS RF power amplifier is described. It is built without using inductors, to investigate what performance then can be achieved. Lund, 1998 Henrik Sjoland

13 Acknowledgements I would like to thank my advisor professor Sven Mattisson, without whom I would not have been able to perform the work on which this book is based. I would also like to thank my parents and all colleagues and friends at the Department ofapplied Electronics for their help and encouragement. I am particularly grateful to Dr. Lars Sundstrom for his support during the last year. I would also like to thank Paula, my fiancee for her patience. I am also grateful to professor Mohammed Ismail, who suggested that I would write this book based on my Ph.D. thesis, on which he was the opponent. Financial support has been received from the Swedish National Board for Industrial and Technical Development (NUTEK). Some of the material has appeared in IEEE Transactions on Circuits and Systems and IEEE Journal of Solid-State Circuits. I am very grateful to IEEE for allowing me to reuse this material, which is ofvital importance for this book.