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1、折叠式级联运放的仿真TheTypicalPerformanceofOp-AmpOpen-LoopDifferentialGain(AV)Common-modeRejectionRatio(CMRR)PowerSignalRejectionRatio(PSRR)PhaseMargin(PM)InputCommonModeRange(ICMR)OutputSwingRange(OSR)Input/OutputImpedance(CIN/ROUT)SlewRateNoiseTheSchematicofFoldedCascodeOp
2、-AmpInordertodeceasethepowerConsumption,IBIASisonly30nA.CreateSchematicandSymbolinSpectreTocreateasymbolofaschematic:FromDesign->CreateCellview->FromCellviewOpen-LoopDifferentialGainDCSweepVP-VN(largesignal)ACSweepVP-VNwithfixedfrequency(smallsignal)Twomethodsofsim
3、ulatingOpen-LoopDifferentialGainisavailableinADE(AnalogDesignEnvironment)Test-BenchofOpen-LoopDifferentialGain(method1)DCSweepVP-VN(largesignal)Inthismethod,VP=VCM_IN+x,andVN=VCM_IN-xWhere,VCM_INisthecommonvoltage,xisadesignvariables.SetupVNSetupVPADEofOpen-LoopDif
4、ferentialGain(method1)ToaddamodelforthesimulationFromADE->Setup->ModellibrariesTocreateaDCSweepFromADE->Analyses->Choose->DCWaveformofOpen-LoopDifferentialGain(method1)Where,DifferentialGainis71.56dBToobtainVCOM_OUTFromCalculator->SpecialFunctions->ValueVOUT-VCOM_O
5、UTToobtainDCgainFromCalculator->SpecialFunctions->derivTest-BenchofOpen-LoopDifferentialGain(method2)ACSweepVP-VNwithfixedfrequencySetupVNSetupVPInthismethod,VP=VCM_IN+x+VAC,andVN=VCM_INWhere,VCM_INistheinputcommonvoltage,xisadesignvariables,VACisaACvoltageforACSwe
6、ep.ADEofOpen-LoopDifferentialGain(method2)ToaddamodelforthesimulationFromADE->Setup->ModellibrariesTocreateaACSweepFromADE->Analyses->Choose->ACFixedFreqWaveformofOpen-LoopDifferentialGain(method2)DifferentialGainis65.56dBTheresultsofthetwomethodsaredifferent,Infac
7、t,method1ismoreaccurateforDCgain.Common-modeRejectionRatioYoucangetdetailillustrationfrom“CMOSAnalogCircuitDesign”,PhillipE.Allen,OxfordUniversityPress,Inc.Test-BenchofCMRRWhere,VCOM_INistheinputcommonvoltage,VACisaACvoltageforACSweep.ADEofCMRRToaddamodelforthesimu
8、lationFromADE->Setup->ModellibrariesTocreateaACSweepFromADE->Analyses->Choose->ACWaveformofCMRR1/CMRRCMRRToobtainCMRR:FromCalculator->1/x1/CMRRan