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ID:39469579
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页数:7页
时间:2019-07-04
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1、Allrightsreserved.HSPICE,SYNOPSYS.Inthisdocument,youwillseethecircuitconstructionofa“voltagecontrolledoscillator”andhowdifferentkeyparametersaresimulatedwithHSPICERF.VCOVoltagecontrolledoscillator(VCO)iswidelyusedinwirelesscommunicationsystems,suchasfrequencysynthesizer.AhighperformanceVCOshou
2、ldbecarefullyconsideredfromalotofaspects.HSPICERFprovidespowerfultools,whichtakecareofeverycharacteristicsofVCOandmakecomplicateddesigneasytoimplement.Belowisthecircuitschematicthatwewilldiscussinthisdocument:Figure1.VCOschematicInthispart,avcoisdesignedtooscillateat1.6v.1.OscillatorSimulation
3、–Steady-StateSignalSimulationInthisfigure,M4~M7areparallelconnectedPMOS,whichareusedasvaractorsforfrequencytuningpurpose;M1~M3offersnegativeconductancetofulfilltheoscillatingpre-condition;R0andR1isusedtorepresenttheparasiticresistanceofL0andL1;m_multisaparameter,whichisdefinedastheparallelconn
4、ectedPMOSsnumber.Bytuningthem_multvalue,wecangetafrequencyvaluethatmorecloseto1.6GHz.Inordertoachieveaproperm_mult,wecanusesnsweepfunction.Here,SynospsysSIMIFisusedtosetupnewanalysisandgeneratenetlist.Thesettingisshownbelow.Thissettingwillinsertacommandas.sntone=1.6gnharms=10trinit=100noscnode
5、=out1SWEEPm_multLIN10500560intonetlist.Severalwayscanbeusedtostimulateanoscillator·UsingIConaninductor·UsingaPWLsourcetoinjectapulseorrampVDD.·UsingUICoptionintheanalysiscommand.Here,weusethefirstmethod.Addaprobecommandinanincludefile(inc1.spi)as.probesnfdparam=Hertz[1]ThesnresultwillbeSo,weca
6、nsetm_mult=518asthenumberthatwewilluselater.1.PhasenoiseAsotheranalogcircuits,oscillatorsaresusceptibletonoise.Innoisyenvironment,outputsignalwillchangeinamplitudeandperiod.Phasenoiseisusedtoevaluateoscillator’srandomdeviationofthefrequency.HSPICERFhasthespecial.phasenoisecommandtosupportnon-a
7、utonomouscircuitsimulation.Phasenoisecanonlybeusedwith.snor.hb.BelowisSIMIFsettingtoperformphasenoiseanalysis:Itwillinsert.phasenoisev(out1)DEC101K10e6intothenetlist.AndthesimulationresultisSo,thephasenoiseis-96.25dBc@60KHz.1.JitterPhas
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