Phase Delay in MAC-based Analog Functional Testing in Mi：在MI基于MAC的相位延迟的模拟功能测试

PhaseDelayinMAC-basedAnalogFunctionalTestinginMixed-SignalSystemsJieQin,CharlesStroud,andFosterDaiDept.ofElectricalandComputerEngineering200BrounHall,AuburnUniversity,AL36849-5201

04/26/20061OutlineMotivationandBackgroundBuilt-InSelf-TestArchitecturePhaseDelayintheMAC-basedORAExperimentalResultsConclusions04/26/20062MotivationandBackgroundWhymixed-signalBIST?Theincreasingcostoffunctionalitytestbasedonthetraditionalmethodologyofexternaltestequipmentformodernmixed-signalICs.TheincreasingdifficultytoperformtestontheseICs.Witharapidlyincreasinglevelofintegration,thenumberofinput/output(IO)pinsdoesnotincreaseaccordingly.TheoperationalfrequencyoflatestanalogICsatGHzrequirestesterelectronicsveryclosetotheDUT.04/26/20063MotivationandBackground(cont.)Whatshouldamixed-signalBISTbe?ItcanextractthefrequencyspectruminformationofthesignalcomingfromtheDUT.LinearityMeasurementFrequencyResponseSignal-to-NoiseRatioMeasurementItshouldbeimplementedusingsimplecircuitrywithsmallareapenaltyandshouldnotcauseperformancepenaltytoanalogcircuitry.TheconventionalwaytoobtainthefrequencyspectrumisFFT.However,theareapenaltyandpowerconsumptionintroducedbyaFFTprocessorisnotwhataBISTexpects.04/26/20064MotivationandBackground(cont.)TheBISTapproachbasedontheDDS-basedTPGandMAC-basedORAwasproposed.DDS-basedTPGcangeneratevariouswaveformswhichisrequiredforthelinearity,frequencyresponse,andSNRmeasurement.MAC-basedORAcouldberealizedinamuchsimpler,cheaperandmoreflexiblecircuit,comparedwiththeFFT-basedORA.04/26/20065Built-InSelf-TestArchitectureMostoftheBISTcircuitryresidesinthedigitalportionofthemixed-signalsystem.Insuchaway,theperformancepenaltyareminimized.ThenumberandlocationoftheMUXinsertedtothesystemdeterminestheaccuracyoftheanalogfunctionalmeasurements.AmpTestControllerMUX1MUX2NCO1NCO2NCO3Sin(2f1’nTclk+1)f1’,1Sin(2f2’nTclk+2)f2’,2f3’,3Sin(2f3’nTclk+3)DACDUTMUX3ADCMUX4Accm1Accm2DC1DC2MUL1MUL2f1(nTclk)f2(nTclk)f(nTclk)TestPatternGenerator(TPG)OutputResponseAnalyzer(ORA)04/26/20066MAC-basedORAWhileperformingtheanalogfunctionaltesting,theDC1andDC2accumulatorvaluescanbedescribedas

Thenthethesignalf(nTclk)’sFourierTransformF()canbeexpressedthroughDC1andDC2ThemagnituderesponseA()andthephasedelayΔΦ()arethetwoparameterswidely

usedmuchmorewidelyinfunctionalmeasurementsofanalogcircuits.04/26/20067PhaseDelayinMAC-basedORAHowcanthephasedelaybeevaluated?Foranon-chiptest,wedon’thavetosetupafull-lengtharctanlook-uptable(LUT)tocalculateΔΦ().FirsttheabsolutephaseoffsetΔΦo()needtobecalculatedaccordingtothefollowingformula:

04/26/20068PhaseDelayinMAC-basedORA(cont.)ThenthephasedelaycanbedeterminedthroughtheabsolutephaseoffsetΔΦo()accordingtothefollowingtable:|DC1|≥|DC2||DC1|≤|DC2|DC1>0;DC2>0Df(w)=Dfo(w)

Df(w)=90-Dfo(w)

DC1>0;DC2<0Df(w)=360-Dfo(w)

Df(w)=270+Dfo(w)

DC1<0;DC2>0Df(w)=180-Dfo(w)

Df(w)=90+Dfo(w)

DC1<0;DC2<0Df(w)=180+Dfo(w)

Df(w)=270-Dfo(w)

Thearctanlook-uptable(LUT)canbedecreasedbyhalfbecausethevaluerangeofΔΦo()variesfrom0to45.

whenDC2/DC1isverysmall,thearctan(DC2/DC1)canberepresentedbytheratiooftheDC2/DC1.Sothelengthofthearctanlook-uptable(LUT)canbecompressedfurther.04/26/20069PhaseDelayinMAC-basedORA(cont.)Oncethephasedelayisidentified,themagnituderesponseA()canbecalculatedthroughthefollowingapproaches.Approach#1Approach#2Approach#304/26/200610PhaseDelayinMAC-basedORA(cont.)ProsandconsofthethreeapproachesApproach#1#2#3HardwareoverheadlowhighhighspeedlowhighhighconstraintsItcannotbeusedforSNRMeasurement.nonopropagationerroryesyesno04/26/200611ExperimentalResultsIThephasedelayintroducedbythedigitalportionoftheBISTcircuitry.phaseerrorduetothedelayinTPGphaseerrorwithdelayremoved04/26/200612ExperimentalResultsIIThephasedelayintroducedbytheADC/DACpair04/26/200613ExperimentalResultIIITheresourcesusedbytheMAC-basedORA.#ofinputbits,N81216#ofoutputbits,M2874129-3276131204367813320640801352084482137210#ofinputbits,N81216#ofoutputbits,M28139244-32143248387361472523914015125639544155260399Numberofslicesvs.MACconfiguration

NumberofLUTsvs.MACconfiguration

04/26/200614ExperimentalResultIVTheresourcesusedbyaFFT-processorType#ofslices#of1818-bitmultiplierstransformfrequencyPipelined263312641kHzBurstI/O27439313kHzMinimumResources14123133kHz04/26/200615ComparisonoftheMAC-basedORAandFFT-basedORAMAC-basedORAismuchsimplerandcheaper.MAC-basedORAismoreflexible.thefrequencyresolutioncanbeeasilytunedwiththestepsizeofthesweepingfrequency;itcanmeasuretheinterestedspectruminformationatseveralfrequencypointsorinanarrowbandwidtheasily.04/26/200616Conclusionphasedelayisv