CMOS DATA CONVERTERS FOR COMMUNICATIONS

1 CMOS data CONVERTERSFOR COMMUNICATIONSTHE KLUWER INTERNATIONAL SERIESIN ENGINEERING ANDCOMPUTER SCIENCEANALOG CIRCUITS AND SIGNAL PROCESSINGC onsulting Editor: Mohammed Ismail. Ohio State UniversityRelated Titles:ANALOG SIGNAL GENERATION FOR BIST OF Roberts, LuISBN: 0-7923-9564-6 INTEGRATED FIBER-OPTIC RECEIVERSA. Buchwald, : 0-7923-9549-2 MODELING WITH AN ANALOG HARDWARE DESCRIPTION Mantooth, M. FiegenbaumISBN: 0-7923-9516-6 LOW-VOLTAGE CMOS OPERATIONAL AMPLIFIERS: Theory, Design andImplementationS. Sakurai, M. IsmailISBN: 0-7923-9507-7 ANALYSIS AND SYNTHESIS OF MOS TRANSLINEAR CIRCUITSR. WiegerinkISBN: 0-7923-9390-2 COMPUTER-AIDED DESIGN OF ANALOG CIRCUITS AND Carley, GryurcsikISBN: 0-7923-9351-1 HIGH-PERFORMANCE CMOS CONTINUOUS-TIME FILTERSJ. Silva-Mart nez, M. Steyaert, W. SansenISBN: 0-7923-9339-2 SYMBOLIC ANALYSIS OF ANALOG CIRCUITS: Techniques and Huelsman, GielenISBN: 0-7923-9324-4 DESIGN OF LOW-VOLTAGE BIPOLAR OPERATIONAL Fonderie, HuijsingISBN: 0-7923-9317-1 STATISTICAL MODELING FOR COMPUTER-AIDED DESIGN OF MOS VLSICIRCUITSC.

2 Michael, M. IsmailISBN: 0-7923-9299-XSELECTIVE LINEAR-PHASE SWITCHED-CAPACITOR AND DIGITALFILTERSH. BaherISBN: 0-7923-9298-1 ANALOG CMOS FILTERS FOR VERY HIGH FREQUENCIESB. NautaISBN: 0-7923-9272-8 ANALOG VLSI NETWORKSY. TakefujiISBN: 0-7923-9273-6 CMOS data CONVERTERSFOR COMMUNICATIONSbyMikaelGustavssonGlobeSpa n, Jacob WiknerEricsson Components ABandNianxiong Nick TanGlobeSpan, PUBLISHERS NEW YORK, BOSTON, DORDRECHT, LONDON, MOSCOWeBook ISBN:0-306-47305-4 Print ISBN:0-792-37780-X 2002 Kluwer Academic PublishersNew York, Boston, Dordrecht, London, MoscowAll rights reservedNo part of this eBook may be reproduced or transmitted in any form or by any means, electronic,mechanical, recording, or otherwise, without written consent from the PublisherCreated in the United States of AmericaVisit Kluwer Online at: Kluwer's eBookstore at: the late Vanja GustavssonMikael GustavssonTo Ulrica and my familyJ Jacob WiknerTo Regina and DianaN.

3 Nick TanCONTENTSP refaceAbbreviations and Acronymsxvxix1 CHARACTERIZATION OF DATACONVERTERS Ideal data ConverterQuantizationStatic Nonlinearity (DNL)Integral Nonlinearity (INL)Offset Errors in DACsGlitches in DACsClock Feedthrough(CFT) in DACsSampling Time Uncertainty in DACsDynamic Errors in Ratio (SNR)SpuriousFree Dynamic Range (SFDR)Harmonic Distortion (HDk)Total Harmonic Distortion (THD) and Distortion Ratio (SNDR) Effective Number Of Bits (ENOB) Peak Dynamic Range (DR) Effective Resolution Bandwidth (ERB)Intel-Modulation Distortion (IMD)SNR with Multi-Tone InputMulti-Tone Power Ratio (MTPR) data CONVERTERS for Communications2 data CONVERTERREQUIREMENTS Coding CodesPassband CodesExcess MethodMulti-CarrierSystemsMinimumData converter for BasebandDAC for PassbandDAC for DMTADC RequirementsInfluence of for Requirements for Wideband IF OVERVIEW OFHIGH-SPEED (S/H) NoiseNonlinearity ErrorsDynamicErrorsSignal Dependent Delayin and Sigma-Delta ADCs 72 Low SpeedConvertersTime-Interleaved(Parallel )

4 OVERVIEW OF D/ACONVERTER with WeightedDAC DACR-2 RLadder DACC hargeRedistribution DAC ArchitectureEncoded DACA rchitectureHybrid DACA rchitectureLow-Speed DAC DAC ArchitectureSwitched-CurrentAlgorithmic DACA rchitectureOversampling D/AConverter (OSDAC) andInterpolationFiltersSigma-Delta ModulatorM-bit Randomization and Element ComparisonSummary1191215 OVERVIEWOF ErrorsNoisexCMOS data CONVERTERS for and ClockFeedthrough ANALOGFUNCTIONAL Multiplying DACMDACs in SI Pipelined ADCsPerformance Limitations in AmplificationDistributing Currents toSeveralOutputsTime-InterleavedStageD/A of SI MDACSSC ofFiniteOpampGain andParasitic In SC Noise inOpampInputReferredThermalNoise of SCAmplifier IInputReferredThermalNoise of SCAmplifier IIThermalNoise in Opamp GainEffect ofFiniteBandwidth and Finite ANALOGCIRCUIT Rate OpampTelescopicOpampGain Boosting ComparatorMetal Stability andErrorProbabilityOffset CancellationTechniquesCircuit and Reference GenerationCurrentReference Summary 2028 LOW-VOLTAGE

5 ANALOG ofScalingLow GeneratorBootstrapSwitchingLevelConversi on Opamp TechniqueSummary2242269 PIPELINEDA/D Pipelined ADCSub DACR esidue and S/HAmplifierxiiCMOS data CONVERTERS for and in ErrorsS/H AmplifierErrorsDAC ofNon-Ideal Opamp GainNoiseLimited BandwidthLimitedSlew RateMatchingHow to Choose TIME-INTERLEAVEDA/D of Time-InterleavedADCsErrors inTime-Interleaved ErrorsPhase Skew in SC Time-InterleavedADCsImproved PassiveSamplingTechniqueEffect ofParasitic of theImproved Sampling S/HCircuitOpamp Skew OVERSAMPLINGA/D of Oversampling Sigma-Delta ConvertersOversampled Sigma-Delta CONVERTERS for High Signal Fourth Order Cascaded ModulatorImproved 2-2 Cascaded Modulator2-1-1 CascadedModulatorCascaded Modulator with Multi-Bit OpampGainFiniteBandwidthNon-linear SettlingCapacitor MismatchGain Errors in Cascaded ModulatorsThermalNoiseComparator ErrorsNon-linear ExampleSummary31131912 MODELING OF NYQUIST D/A in Current-Steering Error Sources in and INL vs.

6 Output resistanceSNDR vs. Output ResistanceSFDR vs. Output ResistanceInfluence of Parasitic Source vs. MismatchSFDR vs. MismatchImpact of Correlated and Graded Matching of Circuit NoiseInfluence of Dynamic Skew and data CONVERTERS for Communications13 IMPLEMENTATION OF CMOSCURRENT-STEERING D/A DAC StructureSegmented StructuresCurrent Cell Matrix of Current SourcesCurrent SwitchesDigital CircuitsCurrentSource CMOS Current-Steering DAC Current Sources and Source ArrayCurrent ResultsConclusions and In the telecommunication era, analog design is not just a matter of isolatedself-satisfying circuit tweaking, it is above all a system planning. Digital radio and high-speed internet access have created a great demand on high-per-formance data CONVERTERS . The conventional view of dataconverters as numerical con-version blocks does not suffice for this kind of communication applications.

7 From acommunication system s perspective, the bit error rate (BER) requirement determinesthe signal-to-noise ratio (SNR) requirement for a given modulation and duplexingscheme. Therefore,when we design data CONVERTERS for a communication system, fre-quency-domain measures such as the SNR are of great importance. In theory, anyknown distortion components in a transmit channel of a communication system can becorrected by measuring it through the use of a pilot signal or during the initializationphase. But in practice, it is difficult to predict the distortions due to the time-varyinginterference of adjacent channels in most communication systems. Therefore, the dis-tortion and inter-modulation of data CONVERTERS are of great importance as well. Theuse of discrete multi-tone (DMT)modulation for digital subscriber line (DSL) and theuse of orthogonal frequency division multiplexing (OFDM) for wideband radio fur-ther complicate the data converter design in that even the single-tone frequency-do-mainmeasures do not universities teachanalogcourses as circuit design courses with little interactionwith communication or designers can only de-sign circuits specified by system engineers without much understanding of the system,and most system engineers have not much knowledge about analog combination usually results in non-optimal system solutions.

8 If analog designerswith the system knowledge participate in the systemspecification and system parti-tioning, we can really design the optimal system with judicious trade-offs between an-alog and digital, software and hardware. By realizing the industrial and educationalneed of analog designers with system knowledge, the Microelectronics ResearchCenter of Ericsson startedanalogactivitieswith close cooperations with Link pingUniversity in 1995. One of the results is this data CONVERTERS for communicationsaddressesanalog design for communica-tion systems. It distinguishes itself from other data converter books by emphasizingsystem-related aspects of data converter designs and frequency-domain performanceof data CONVERTERS . However,this is not a book written by system designers rather thanby circuit designers.

9 It therefore also coverscircuit designs and implementations ofxvi CMOS data CONVERTERS for CommunicationsCMOS data CONVERTERS , based on measured data CONVERTERS for COMMUNICATIONS bridges the gap between the communica-tion system requirements and the mixed signal design. It derives data converter re-quirements from the communication system specifications such as line codes,modulation schemes, and duplexing methods, etc. It also gives examples of relatingasymmetrical DSL(ADSL) andwideband ratiosystems to the dataconverter data CONVERTERS for communicationscan be used asa reference book byanalogcircuit designers to understand the data converterrequirements for can also be used by communication system designers to understand the difficultiesof certain performance requirements on data CONVERTERS .

10 This book reflects the authorsmany yearphilosophy in bothindustrial practice and academic education. In the tele-communication era, analog design is not just a matter of isolated self-satisfying circuittweaking, it is above all a system planning. To prepare analog students for the newchallenge, thisbook can be an excellent book consists of 13 chapter 1, we discuss the characterization of data converterswith emphasis on fre-quency-domain measures. It also discusses the multi-tone power ratio (MTPR) meas-ure for DMT or OFDM applications. It is shown that multi-carrier modulations usuallyhave a higher dynamic range requirement on data CONVERTERS due to the instantaneoussummation of many carriersresulting in a large peak to average ratio (PAR).In chapter 2, we first briefly discuss the fundamentals of digital communication sys-tems and introduce the relevant terminologies such as bit error rate (BER),line codes,modulation schemes, and duplexing methods, etc.