CMOS SIGMA-DELTACONVERTERS

CMOS SIGMA-DELTACONVERTERSPRACTICAL DESIGN GUIDE

Jose M. de la Rosa and Rocıo del RıoUniversity of Seville, Spain

A John Wiley & Sons, Ltd., Publication

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Library of Congress Cataloging-in-Publication Data

Rosa, Jose M. de la.CMOS sigma-delta converters : practical design guide / Jose M. de la Rosa and

Rocio del Rio.pages cm

Includes bibliographical references and index.ISBN 978-1-119-97925-8 (hardback : alk. paper) — ISBN 978-1-118-56922-1

(ebook/epdf) — ISBN 978-1-118-56843-9 (epub) — ISBN 978-1-118-56842-2 (mobi)—ISBN 978-1-118-56923-8 1. Metal oxide semiconductors, Complementary—Design andconstruction. I. Title.

TK7871.99.M44R668 2013621.3815′9—dc23

2012041956

A catalogue record for this book is available from the British Library.

ISBN: 978-1-119-97925-8

Set in 10/12pt Times by Laserwords Private Limited, Chennai, India

This book is dedicated to the memory of my son Jose ManuelJose M. de la Rosa

To my wife Visi, my daughter Marıa, my son Jaime,my parents Carmen and Juan, and my parents-in-law

Marıa Luisa and Jose AntonioJose M. de la Rosa

To my husband Juanan and my son MarioRocıo del Rıo

“If you love what you do and are willing to do what it takes,it’s within your reach. And it’ll be worth every minute youspend alone at night, thinking and thinking about what it isyou want to design or build. It’ll be worth it, I promise.”

Steve Wozniak (iWoz, 2006)

Contents

List of Abbreviations xvii

Preface xxi

Acknowledgements xxvii

1 Introduction to �� Modulators: Basic Conceptsand Fundamentals 1

1.1 Basics of A/D Conversion 21.1.1 Sampling 21.1.2 Quantization 31.1.3 Quantization White Noise Model 41.1.4 Noise Shaping 7

1.2 Basics of Sigma-Delta Modulators 81.2.1 Topology of �� ADCs 81.2.2 Signal Processing in ��Ms 91.2.3 Performance Metrics of ��Ms 101.2.4 Performance Enhancement of ��Ms 13

1.3 Classification of �� Modulators 151.4 Single-Loop �� Modulators 16

1.4.1 Second-Order ��M 161.4.2 High-Order ��Ms 20

1.5 Cascade �� Modulators 241.6 Multibit �� Modulators 29

1.6.1 Influence of Multibit DAC Errors 301.6.2 DEM Techniques 311.6.3 Dual Quantization 34

1.7 Band-Pass �� Modulators 361.7.1 The z → −z2 LP–BP Transformation 371.7.2 BP-��Ms with Optimized NTF 39

1.8 Continuous-Time �� Modulators 411.8.1 DT–CT Transformation of ��Ms 441.8.2 Direct Synthesis of CT-��Ms 48

xii Contents

1.9 Summary 49References 49

2 Circuits and Errors: Systematic Analysis and Practical Design Issues 542.1 Nonidealities in Switched-Capacitor �� Modulators 552.2 Finite Amplifier Gain in SC-��Ms 562.3 Capacitor Mismatch in SC-��Ms 602.4 Integrator Settling Error in SC-��Ms 62

2.4.1 Behavioral Model for the Integrator Settling 622.4.2 Linear Effect of Finite Amplifier Gain-Bandwidth Product 672.4.3 Nonlinear Effect of Finite Amplifier Slew Rate 682.4.4 Effect of Finite Switch On-Resistance 69

2.5 Circuit Noise in SC-��Ms 712.6 Clock Jitter in SC-��Ms 752.7 Sources of Distortion in SC-��Ms 76

2.7.1 Nonlinear Amplifier Gain 772.7.2 Nonlinear Switch On-Resistance 78

2.8 Nonidealities in Continuous-Time �� Modulators 802.9 Clock Jitter in CT-��Ms 81

2.9.1 Jitter in Return-to-Zero DACs 822.9.2 Jitter in NonReturn-to-Zero DACs 832.9.3 Jitter in Switched-Capacitor DACs 84

2.10 Excess Loop Delay in CT-��Ms 852.11 Quantizer Metastability in CT-��Ms 882.12 Finite Amplifier Gain in CT-��Ms 892.13 Time-Constant Error in CT-��Ms 922.14 Finite Integrator Dynamics in CT-��Ms 942.15 Circuit Noise in CT-��Ms 952.16 Sources of Distortion in CT-��Ms 97

2.16.1 Nonlinearities in the Front-End Integrator 972.16.2 Intersymbol Interference in the Feedback DAC 98

2.17 Case Study: High-Level Sizing of a ��M 992.18 Summary 107

References 107

3 Behavioral Modeling and High-Level Simulation 1103.1 Systematic Design Methodology of �� Modulators 110

3.1.1 System Partitioning and Abstraction Levels 1103.1.2 Sizing Process 112

3.2 Simulation Approaches for the High-Level Evaluation of ��Ms 1133.2.1 Alternatives to Transistor-Level Simulation 1143.2.2 Event-Driven Behavioral Simulation Technique 1163.2.3 Programming Languages and Behavioral Modeling Platforms 117

3.3 Implementing ��M Behavioral Models 1183.3.1 From Circuit Analysis to Computational Algorithms 1183.3.2 Time-Domain versus Frequency-Domain Behavioral Models 121

Contents xiii

3.3.3 Implementing Time-Domain Behavioral Models in MATLAB 1243.3.4 Building Time-Domain Behavioral Models as SIMULINK

C-MEX S-Functions 1283.4 Efficient Behavioral Modeling of ��M Building Blocks using

C-MEX S-Functions 1343.4.1 Modeling of SC Integrators using S-Functions 1343.4.2 Modeling of CT Integrators using S-Functions 1483.4.3 Behavioral Modeling of Quantizers using S-Functions 153

3.5 SIMSIDES: A SIMULINK-Based Behavioral Simulator for ��Ms 1593.5.1 Model Libraries Included in SIMSIDES 1593.5.2 Structure of SIMSIDES and User Interface 163

3.6 Using SIMSIDES for the High-Level Sizing and Verificationof ��Ms 1673.6.1 SC Second-Order Single-Bit ��M 1683.6.2 CT Fifth-Order Cascade 3-2 Multibit ��M 177

3.7 Summary 183References 184

4 Circuit-Level Design, Implementation, and Verification 1864.1 Macromodeling ��Ms 186

4.1.1 SC Integrator Macromodel 1874.1.2 CT Integrator Macromodel 1894.1.3 Nonlinear OTA Transconductor 1914.1.4 Embedded Flash ADC Macromodel 1914.1.5 Feedback DAC Macromodel 1924.1.6 Examples of ��M Macromodels 195

4.2 Including Noise in Transient Electrical Simulations of ��Ms 1994.2.1 Generating and Injecting Noise Data Sequences in HSPICE 2014.2.2 Analyzing the Impact of Main Noise Sources in SC Integrators 2034.2.3 Generating and Injecting Flicker Noise Sources in

Electrical Simulations 2044.2.4 Test Bench to Include Noise in the Simulation of ��Ms 207

4.3 Processing ��M Output Results of Electrical Simulations 2084.4 Design Considerations and Simulation Test Benches

of ��M Basic Building Blocks 2134.4.1 Design Considerations of CMOS Switches 2144.4.2 Design Considerations of Operational Amplifiers 2224.4.3 Design Considerations of Transconductors 2304.4.4 Design Considerations of Comparators 2364.4.5 Design Considerations of Current-Steering DACs 242

4.5 Auxiliary ��M Building Blocks 2504.5.1 Clock-Phase Generators 2504.5.2 Generation of Common-Mode Voltage, Reference Voltage,

and Bias Currents 2534.5.3 Additional Digital Logic 256

xiv Contents

4.6 Layout Design, Floorplanning, and Practical Issues 2574.6.1 Layout Floorplanning 2574.6.2 I/O Pad Ring 2594.6.3 Importance of Layout Verification and Catastrophic Failures 261

4.7 Chip Package, Test PCB, and Experimental Set-Up 2634.7.1 Bonding Diagram and Package 2644.7.2 Test PCB 2644.7.3 Experimental Test Set-Up 266

4.8 Summary 270References 270

5 Frontiers of �� Modulators: Trends and Challenges 2735.1 Overview of the State of the Art on ��Ms 274

5.1.1 DR-versus-Bw Conversion Region 2865.1.2 Conversion Energy and Figures of Merit 287

5.2 Empirical and Statistical Analysis of State-of-the-Art ��Ms 2915.2.1 SC versus CT State-of-the-Art ��Ms 2915.2.2 Gm-C versus Active-RC State-of-the-Art CT-��Ms 2925.2.3 Technology Used in State-of-the-Art ��Ms 2955.2.4 Single-Loop versus Cascade State-of-the-Art ��Ms 2955.2.5 Single-Bit versus Multibit State-of-the-Art ��Ms 2965.2.6 Low-Pass versus Band-Pass State-of-the-Art ��Ms 299

5.3 Cutting-Edge ��M Architectures and Techniques 3005.3.1 SMASH ��M Architectures 3015.3.2 Hybrid ��Ms 3045.3.3 Multirate ��Ms 3075.3.4 Multibit ��Ms with Time-Coded Quantization 3105.3.5 Mostly Digital ��Ms 3115.3.6 Adaptive/Reconfigurable ��Ms 3145.3.7 Ultra-High-Speed CT-��Ms for RF Digitization 315

5.4 Classification of State-of-the-Art References 3195.5 Summary 319

References 320

A SIMSIDES User Guide 334A.1 Getting Started: Installing and Running SIMSIDES 334A.2 Building and Editing ��M Architectures in SIMSIDES 335A.3 Analyzing ��Ms in SIMSIDES 337A.4 Example 345A.5 Getting Help 354

B SIMSIDES Block Libraries and Models 355B.1 Overview of SIMSIDES Libraries 355B.2 Ideal Libraries 355

B.2.1 Ideal Integrators 355B.2.2 Ideal Resonators 357

Contents xv

B.2.3 Ideal Quantizers 358B.2.4 Ideal D/A Converters 360

B.3 Real SC Building-Block Libraries 361B.3.1 Real SC Integrators 361B.3.2 Real SC Resonators 364

B.4 Real SI Building-Block Libraries 364B.4.1 Real SI Integrators 364B.4.2 Real SI Resonators 366B.4.3 SI Errors and Model Parameters 368

B.5 Real CT Building-Block Libraries 371B.5.1 Real CT Integrators 372B.5.2 Real CT Resonators 378

B.6 Real Quantizers and Comparators 382B.7 Real D/A Converters 382B.8 Auxiliary Blocks 384

Index 389

List of Abbreviations

�� Sigma-delta��M Sigma-delta modulator

AAF Antialiasing filterAC Alternate currentA/D Analog-to-digitalADC Analog-to-digital converterADSL Asymmetric digital subscriber lineAMPS Advanced mobile phone systemASIC Application-specific integrated circuit

BB BasebandBE Backward-EulerBGA Ball grid arrayBP Band-passBP-��M Band-pass sigma-delta modulatorBPF Band-pass filter

CAD Circuit aided designCDMA Code division multiple accessCDS Correlated double samplingCLA Clocked averagingCMFB Common-mode feedbackCMOS Complementary MOSFETCPU Central processing unitCS Current-steeringCT Continuous-timeCT-��M Continuous-time sigma-delta modulator

D/A Digital-to-analogDAC Digital-to-analog converterDC Direct currentDCL Digital cancelation logicDEM Dynamic element matchingDMT Discrete multitone

xviii List of Abbreviations

DNL Differential nonlinearityDOR Digital output rateDR Dynamic rangeDRC Design rule checkerDSP Digital signal processorDT Discrete-timeDT-��M Discrete-time sigma-delta modulatorDVB Digital video broadcastingDVB-H Digital video broadcasting - handheldDWA Data weighted averaging

EDGE Enhanced data-rates for global evolutionELD Excess loop delayENOB Effective number of bitsESD Electrostatic discharge

FE Forward-EulerFFT Fast Fourier transformFIR Finite impulse responseFOM Figure of meritFS Full scale

GB Gain-bandwidth productGPS Global positioning systemGSM Global system for mobile communicationsGUI Graphic user interface

H-��M Hybrid sigma-delta modulatorHD Harmonic distortionHDL Hardware description languageHRZ Half-delay return-to-zero

IBN In-band noise powerIC Integrated circuitIF Intermediate frequencyIIP Input-referred intercept pointIIR Infinite impulse responseIIT Impulse-invariant transformationILA Individual level averagingIM Intermodulation distortionINL Integral nonlinearityI/O Input–outputI/Q Inphase/quadratureISI Intersymbol interferenceITF Integrator transfer function

LDI Lossless discrete integratorLNA Low-noise amplifierLP Low-pass

List of Abbreviations xix

LP-��M Low-pass sigma-delta modulatorLPE Layout parasitic extractorLPF Low-pass filterLSB Least significant bitLTE Long term evolutionLTCC Low-temperature co-fired ceramicLTI Linear time-invariantLVS Layout versus schematic

MASH Multistage noise shapingMEX MATLAB executableMiM Metal-insulator-metalMoM Metal-oxide-metalMOS Metal-oxide-semiconductorMOSFET MOS field-effect transistorMOST MOS transistorMR MultirateMR-��M Multirate sigma-delta modulatorMTPR Multitone power ratio

nMOS n-channel MOSFETNRZ Nonreturn-to-zeroNTF Noise transfer function

OL Overload levelOS Output swingOSR Oversampling ratioOTA Operational transconductance amplifier

PCB Printed circuit boardPDF Probability density functionPDM Pulse-density modulationPLL Phase-locked looppMOS p-channel MOSFETPSD Power spectral densityPWL Piece-wise linearPWM Pulse-width modulation

QFP Quad flat package

RF Radio frequencyRTF Resonator transfer functionRZ Return-to-zero

SAR Successive approximation registerSC Switched-capacitorSDR Software-defined radioSFDR Spurious-free dynamic rangeS/H, S&H Sample and hold

xx List of Abbreviations

SI Switched-currentSMASH Sturdy multistage noise shapingSMD Surface-mount deviceSNR Signal-to-noise ratioSNDR Signal-to-noise-plus-distortion ratioSQNR Signal-to-quantization-noise ratioSoC System on chipSR Slew rateSTF Signal transfer function

TDC Time-to-digital converterTEQ Time-encoding quantizerTHD Total harmonic distortion

UGBW Unity gain bandwidthUMTS Universal mobile telecommunications systemUSMR Upsampling multirateUSTF Unity signal transfer function

VCO Voltage-controlled oscillatorVCRO Voltage-controlled ring oscillatorV/I Voltage-to-current

WCDMA Wideband code division multiple accessWiMAX Worldwide interoperability for microwave accessWLAN Wireless local area network

Preface

Sigma-Delta modulators (��Ms) have become one of the best choices for the implemen-tation of analog/digital interfaces integrated in CMOS technologies. Compared to otherkinds of analog-to-digital converters (ADCs), ��Ms cover the widest conversion regionof the resolution-versus-bandwidth plane, being the most efficient solution to digitize verydiverse types of signals in an increasing number of application scenarios, which span fromhigh-resolution low-bandwidth data conversion (like digital audio, sensor interfaces, andinstrumentation) to ultra-low power biomedical systems and medium-resolution broad-band wireless communications. This versatility, together with their robustness and theirsimplicity in many practical situations, has motivated that more and more engineers todayconsider ��Ms as a first choice for their research projects and their industrial products.

The first idea underlying the operation of ��Ms was patented by Cutler in 1960 [1],although its application to the construction of data converters was first reported in thepublished literature by Inose et al in 1962 [2]. The operation of ��Ms is relatively simpleto describe, although sometimes difficult to analyze. Essentially, the fundamental principlebehind ��Ms is based on the combination of two signal processing techniques, namelyoversampling and quantization noise shaping. The former consists of taking the signalsamples at a higher rate than the one dictated by the Nyquist sampling theorem. Thesesamples are commonly quantized with a large error by using a low-resolution quantizer.The resulting oversampled quantization error is filtered in the modulator feedback loop,so that its frequency spectrum is shaped in such a way that a large portion of its poweris pushed out of the signal band, where it is removed by a digital filter. The outcome ofthe combined action of oversampling and noise shaping allows ��Ms to achieve a high-precision digitization by using a low-resolution coarse quantizer. Therefore, unlike otherkinds of ADC architectures that require high-precision analog circuits, ��Ms trade theaccuracy of their analog circuitry by the speed of digital signal processing, thus achievinga higher degree of insensitivity to circuit error mechanisms and potentially benefitingfrom CMOS technology evolution towards the nanometer scale.

Prompted by the mentioned benefits and fueled by technology downscaling and industrytrends in consumer digital electronics, the original concept of noise shaping describedabove has evolved over the last five decades through many ��M generations, givingrise to a pleiad of architectures, circuit and system design techniques, and a numberof Integrated Circuits (ICs), which have pushed the state-of-the-art on ��Ms forward,yielding to innovative research results and successful industry products. All these advancesand research works have lead (and continue doing so) to a vast amount of technical

xxii Preface

literature. Indeed, since the publication of pioneer works like the widely cited paperswritten by Candy [3, 4] and Boser and Wooley [5], the number of publications hasincreased significantly including hundreds of patents, thousands of research papers, sometutorial papers [6–8], as well as tens of introductory and specialized monographs [9–29].However, with so much material and abundance of technical information published, manydesigners—particularly novel designers and also some experienced designers focused ona specific subtopic of ��Ms—may become disoriented and lost. This has motivatedsome authors to put all these pieces of information together in a comprehensive andsystematic way.

Apart from the earlier books aiming to catalogue the existing publications on ��Ms[9], one of the first attempts to present a guide for ��M designers is the book edited byNorsworthy et al in 1997 [10], also known as “the yellow book” by the ��M community.This book deals with a number of important subjects in ��Ms and it was contributed bya number of experts in the field, thus making it more difficult to present its contents ina coherent and consistent way. With this objective in mind, some authors have put theireffort on writing tutorial monographs dealing with the systematic design of ��Ms.

Among others, the book written by Schreier and Temes, published in 2005 [21], oftennamed “the green book”, has become one of the most popular books on �� converters.This book provides an excellent and comprehensive treatment of ��Ms, their operat-ing principles, and main architectures, presenting several design examples constructedusing the well-known Schreier’s MATLAB toolbox [30]. Although some examples ofcontinuous-time (CT) circuit implementations are given, the book mainly focuses onsystem-level description, considering a switched-capacitor (SC) implementation. Someother remarkable examples are the book written by Medeiro et al in 1999 [13]—focusedon the systematic design of SC ��Ms—and the book of Ortmanns and Gerfers [22]published in 2006, which is still one of the most complete monographs on CT ��Msreported to date. All these books, as well as other monographs reported in the technicalliterature, give a partial view of ��Ms, paying more attention to some particular aspectsof the design of ��Ms, and/or a type of architecture, circuit technique, or application.

In this scenario, this book attempts to cover some of these knowledge gaps, by providinga broader and systematic description of the universe of ��Ms, their diverse types ofarchitectures, circuit techniques, analysis and synthesis methods and CAD tools, as wellas their practical design considerations. From this perspective, the book has a twofoldpurpose. First, it constitutes a unique monograph that results from compiling the enormousnumber of technical and research works reported to date on the topic of ��Ms, andpresents the results of such a compilation in a didactical, pedagogical, and intuitive style.The second main objective and a key feature of this book is to serve as a practical guidefor designers, putting emphasis on explaining practical design issues involved in the wholedesign flow of ��Ms: from specifications to chip implementation and characterization.To this end, a top-down approach is followed, presenting the contents in a hierarchicalway; that is, going from theoretical fundamentals, system-level design equations, andbehavioral models to circuit, transistor-level, and physical implementation, in order toprovide readers the necessary understanding and insight into the recent advances, trends,and challenges involved in the design of state-of-the-art ICs.

Indeed, it is the top-down approach adopted in this book that inspires the hierarchicalway in which the contents are organized. Thus, following this introduction, Chapter 1

Preface xxiii

begins from top, giving an introductory survey of ��Ms, their principles of operation,fundamental architectures, analysis and synthesis methods, as well as a taxonomicaldescription of the diverse variety of practical ��M topologies, the nature of signal(low-pass and band-pass), as well as the dynamics involved (either discrete-time orcontinuous-time). In this chapter ��Ms are considered ideal systems, except for theirinherent quantization error. Chapter 2 descends one level in the modulator hierarchy toanalyze the effect of main circuit error mechanisms as well as architectural and timingnonidealities, considered in both SC and CT circuit implementations. The mathematicalmodels, analytical procedures, and design guidelines described in this chapter provide suf-ficient understanding of the main practical problems affecting the performance of ��Msin practice.

The knowledge derived from the first two chapters is presented in this book as anessential part of the systematic top-down/bottom-up synthesis methodology of ��Ms,that is described in Chapter 3. This chapter analyzes different strategies for the high-levelmodeling and simulation of ��Ms, focusing on the so-called behavioral modeling andsimulation techniques. A step-by-step procedure to develop efficient behavioral modelsin the MATLAB/SIMULINK environment is described and illustrated with a number ofexamples of the main ��M building-block models. As an application, a time-domainbehavioral simulator named SIMSIDES, is described and applied to the high-level sizingand verification of some case studies. The contents of this chapter are extended andcomplemented in Appendixes A and B. Appendix A gives a more complete user guide ofSIMSIDES and Appendix B provides an overview of all behavioral models and librariesincluded in this simulator.

Chapter 4 moves farther down from the system-level description given in previouschapters to the circuit and physical level. This chapter provides a number of necessarydesign recommendations and practical recipes to complete the design flow of a ��M,showing the step-by-step methodology to transform a behavioral-model description givenin Chapter 3 into an electrical schematic initially based on macromodels, and then imple-mented with transistors, and finally concluding the design cycle with the layout andchip implementation. Plenty of examples, case studies, and simulation test benches aregiven to illustrate the practical issues and design considerations addressed in the chapter,that cover from electrical analysis and simulation using SPICE-like simulators to layoutdesign considerations, chip prototyping, and experimental measurements of ��Ms in thelaboratory.

To conclude the book, Chapter 5 gives an overview of the state-of-the-art ��M ICs,comparing their performance with Nyquist-rate ADCs. Overall, more than 300 state-of-the-art IC references have been studied in detail and considered in this review, includingpapers published from 1990 to June 2012. Therefore, following the practical philosophythat inspires this book, the diverse families of state-of-the-art ��M architectures and cir-cuit techniques are exhaustively analyzed and compared to extract practical and empiricaldesign guidelines from the statistical data, trying to identify the incoming trends, designchallenges, as well as the solutions proposed by cutting-edge ICs that are in the frontiersof ��Ms.

The book contents are addressed and structured for a large audience: from senior design-ers who want to acquire a deeper and updated insight into ��Ms, to nonexperiencedundergraduate students who are looking for a comprehensive, uniform, and self-contained

xxiv Preface

reference into this hot topic. Bearing this in mind, the style and main purpose of the bookis to serve also as an educational and reference textbook for undergraduate and graduatestudents. Indeed, the book is based on a number of graduate courses given by the authors,including master and doctorate degree programs, invited lectures, and IEEE conferencetutorials. All these materials have been adapted and updated so that a large portion of thebook can be also used (and indeed it has been used) in both undergraduate and graduatecourses.

However, in spite of the encyclopedic nature of the book, it is impossible to give anexhaustive description of all the topics contained in the thousands of publications dealingwith ��Ms. Instead, the book tries to cover the main subtopics, providing sufficientinsight to understand the other ones, that are just overviewed and sometimes even omitted.In order to try to palliate these unavoidable deficiencies, an exhaustive list of specificreferences is included at the end of each chapter. Overall, the book contains around 500selected references in order to guide readers to increase their understanding of the diverseresearch topics dealing with the �� world.

The huge amount of information contained in the book is complemented and updatedwith a number of electronic resources, that have been prepared by the authors and arefreely available on the Web. To this purpose, all the data analyzed in the state-of-the-artsurvey presented in Chapter 5 have been collected in a spreadsheet, which is availableat http://www.imse-cnm.csic.es/∼jrosa/CMOS-SDMs-Survey-IMSE-JMdelaRosa.xlsx.This database is periodically kept up to date and aims to be a complement to thepopular Murmann’s ADC survey data collection [31]. In addition, a fully functionalversion of the time-domain behavioral simulator SIMSIDES is freely available ondemand at http://www.imse-cnm.csic.es/simsides. The simulator includes a number ofexamples, containing the case studies presented in the book and many more examplesand demos. Apart from the SIMSIDES software, the majority of examples and testbenches of different CAD tools used throughout the book are also available on the Webat www.wiley.com/go/delarosa_converters.

Last but not least, it is important to mention that the aforementioned web sites will beregularly updated with new pieces of information and updated material related to the state-of-the-art ��M ICs, SIMSIDES examples and demos, as well as new inputs providedby us and hopefully by our readers. Therefore, your feedback is very important and verywelcomed!

We hope that you enjoy reading this book as much as we have enjoyed writing it.

Jose M. de la Rosa and Rocıo del RıoSevilla, October 2012

References[1] C. C. Cutler, “Transmission System Employing Quantization,” US Patent No. 2,927,962, 1960.[2] H. Inose, Y. Yasuda, and J. Murakami, “A Telemetering System by Code Modulation—�-� Modulation,”

IRE Transactions on Space Electronics and Telemetry , vol. 8, pp. 204–209, September 1962.[3] J. Candy and O. J. Benjamin, “The Structure of Quantization Noise from Sigma-Delta Modulation,” IEEE

Transactions on Communications , pp. 1316–1323, 1981.[4] J. Candy, “A Use of Double Integration in Sigma-Delta Modulation,” IEEE Transactions on Communica-

tions , vol. 33, pp. 249–258, March 1985.

Preface xxv

[5] B. E. Boser and B. A. Wooley, “The Design of Sigma-Delta Modulation Analog-to-Digital Converters,”IEEE Journal of Solid-State Circuits , vol. 23, pp. 1298–1308, December 1988.

[6] P. M. Aziz et al., “An Overview of Sigma-Delta Converters,” IEEE Signal Processing Magazine, vol. 13,pp. 61–84, January 1996.

[7] I. Galton, “Delta-Sigma Data Conversion in Wireless Transceivers,” IEEE Transactions on MicrowaveTheory and Techniques , vol. 50, pp. 302–315, January 2002.

[8] J. M. de la Rosa, “Sigma-Delta Modulators: Tutorial Overview, Design Guide, and State-of-the-Art Sur-vey,” IEEE Transactions on Circuits and Systems I: Regular Papers , vol. 58, pp. 1–21, January 2011.

[9] J. Candy and G. Temes, Oversampling Delta-Sigma Data Converters: Theory, Design and Simulation ,IEEE Press, 1991.

[10] S. R. Norsworthy, R. Schreier, and G. C. Temes, Delta-Sigma Data Converters: Theory, Design andSimulation , IEEE Press, 1997.

[11] J. Cherry and W. Snelgrove, Continuous-Time Delta-Sigma Modulators for High-Speed A/D Conversion ,Kluwer Academic Publishers, 1999.

[12] J. V. Engelen and R. van de Plassche, BandPass Sigma-Delta Modulators: Stability Analysis, Performanceand Design Aspects , Kluwer Academic Publishers, 1999.

[13] F. Medeiro, B. Perez-Verdu, and A. Rodrıguez-Vazquez, Top-Down Design of High-Performance Sigma-Delta Modulators , Kluwer Academic Publishers, 1999.

[14] V. Peluso, M. Steyaert, and W. Sansen, Design of Low-Voltage Low-Power CMOS Delta-Sigma A/DConverters , Kluwer Academic Publishers, 1999.

[15] S. Rabii and B. A. Wooley, The Design of Low-Voltage, Low-Power Sigma-Delta Modulators , KluwerAcademic Publishers, 1999.

[16] L. Breems and J. H. Huijsing, Continuous-Time Sigma-Delta Modulation for A/D Conversion in RadioReceivers , Kluwer Academic Publishers, 2001.

[17] Y. Geerts, M. Steyaert, and W. Sansen, Design of Multi-bit Delta-Sigma A/D Converters , Kluwer AcademicPublishers, 2002.

[18] J. M. de la Rosa, B. Perez-Verdu, and A. Rodrıguez-Vazquez, Systematic Design of CMOS Switched-Current Bandpass Sigma-Delta Modulators for Digital Communication Chips , Kluwer Academic Publish-ers, 2002.

[19] M. Kozak and I. Kale, Oversampling Delta-Sigma Modulators , Springer, 2003.[20] O. Bajdechi and J. Huising, Systematic Design of Sigma-Delta Analog-to-Digital Converters , Kluwer

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Acknowledgements

We would like to express our deepest gratitude to Prof. Belen Perez-Verdu and Prof.Angel Rodrıguez-Vazquez from the University of Sevilla. We are indebted to them forso many things we learnt, not only related to the contents of this book, but also manylife values and skills we have put in practice throughout our professional careers, firstas their PhD students, then as senior researchers, and later as university professors. Ourwarm and special acknowledgement and dedication of this book goes to them.

We are also particularly grateful to our colleagues at the Institute of Microelectronicsof Sevilla and the Department of Electronics and Electromagnetism of the University ofSevilla, especially to Prof. Francisco Fernandez, Dr. Manuel Delgado, Dr. Rafael Castro,Dr. Rafael Domınguez, Dr. Oscar Guerra, Mr. Joaquın Ceballos, and Mr. Miguel AngelLagos. Among them, we are especially grateful to our friend Dr. Fernando Medeiro,with whom we took our first steps in the fascinating world of sigma-delta modulators,working side by side in a number of research and industrial projects. Thank you verymuch Fernando!

We would also like to acknowledge our past and present undergraduate and graduatestudents, especially Dr. Jesus Ruız-Amaya, Mr. Rafael Romay, Dr. Ramon Tortosa, Dr.Alonso Morgado, Dr. Edwin Becerra, Mr. Gerardo Garcıa, Mr. Luis Guerrero-Linares,and Mr. Sohail Asghar. Some pieces of material used for the preparation of this bookhave been adapted from their PhD works, including a number of examples and case stud-ies. Specifically, the first version of SIMSIDES—the time-domain behavioral simulatordescribed in this book— was developed by Dr. Ruız-Amaya as part of his graduate thesis.

We would like to give our thanks to the staff at Wiley, in particular to the editors LizWingett, Laura Bell, Richard Davies, and Peter Mitchell, as well as to the anonymousreviewers of the book proposal for their constructive and valuable comments and sugges-tions, which became very useful for us to make this manuscript a reality, trying to keepa good trade-off between accuracy (resolution) and time to publication (speed). This isindeed a well-known compromise for us as analog designers. We also appreciate our dis-cussions over all these years with so many experts in the field of sigma-delta converters,with whom we had the opportunity to meet at diverse conferences and technical meetings.Many of them were sponsored by the IEEE Circuits and Systems Society and the IEEESolid-State Circuits Society.

In addition to all these great people, our work has been always supported by a numberof National and International Research and Industrial Projects. More recently, our research

xxviii Acknowledgements

was funded by the Spanish Ministry of Economy and Competitiveness (with support fromthe European Regional Development Fund) under contract TEC2010-14825/MIC.

Finally, our most grateful thanks go for our families. None of this would have beenpossible without their love, patience, confidence, and support. Thank you so much foreverything!