TIA-Calculator(极品跨导放大器计算器)

PeakInputCurrent:Entertheexpectedpeakcurrentfromthephotodiode.UnitsareμA.Cstray:Enterthestraycapacitanceofthefeedbackresistorheretoberealistic.Thenumberhereshouldbesomewherebetween0.2and0.5pF.YougetawarningifthecalculatedCFislower.CanputtworesistorsinseriesforRForuseTEEnetworktodealwiththis.Temp:Entertheambienttemperaturehere.ThisnumberaffectstheRfnoiseportionofthenoisecalcualtionsonly.Doesnotmakeawholelotofdifferenceinthetotaloutputnoise.CPHOTODIODE:EnterthephotodiodecapacitanceinpFhere.BODEPlots:Openloopgainisthe20dB/decadebackwardextensionfromtheactualGBWPfrequencyuntilthegainis90dB,thenstraightbacktotheverticalaxis.Therefore,thedominantpoleappearsatsomearbitrarylowfrequency.Sincethedominantpoleloacationisnotimportantforthisanalysis,itsapparentlocationhasnoparticularsignificance.SignalGainistransimpedanceinkΩ,othergainsareindB.ForCFBamplifiers:OpenLoopandNoiseGainPlotsarenormalizedtothe0dBline.CFBRefPlotissimulatedplotoftransimpedance.PulseResponse:Responsetoanidealsquarewaveisshown.Moreimportantinpulsedapplications.Bluedashedplotisthefastestpossibleresponse(maxslewrate@45°phasemargin).RedplotistheresponsewithCF=C-set.IfC-setC-min,phasemarginisbelow45°,possibleoscillations.AmplitudeEnternumbersinthegreenboxesonlyfromdatasheets.Everythingelseiscalculated.Allthesheetsareprotectedtoavoidenterdatainthegreenboxes.Nopassword.Youcanunprotectifyouwanttoseetheequations.Thesheetisdividedinto4horizontalsections:Topleftsectionisforenetringsystemvariables,toprightisforscematicsoftheTIAandmaxpossibleBandwidthwithworstSNRcalculationsforit.NextSectionshows:Openloopgainisthe20dB/decadebackwardextensionfromtheactualGBWPfrequencyuntilthegainis90dB,thenstraightbacktotheverticalaxis.Therefore,thedominantpoleappearsatsomearbitrarylowfrequency.Sincethedominantpoleloacationisnotimportantforthisanalysis,itsapparentlocationhasnoparticularsignificance.othergainsareOpenLoopandNoiseGainPlotsarenormalizedto0dBline.CFBRefPlotissimulatedplotofResponsetoanidealsquarewaveisshown.Moreimportantinpulsedapplications.Bluedashedplotisthefastestpossibleresponse(maxphasemargin).Redplotisthemin,phase,possibleoscillations.AmplitudePartSpecsfromDatasheet:Allthesespecscomefromdatasheets.fCR:Thisistheunitygaincrossoverfrequencythatcanbereadoffoftheopenloopgainplot.Thisshouldbethefrequencyatwhicha-20dB/decadeprojectionofthetheopenloopgaincrossesthe0dBgainline.Insomecasesthisnumbercanbelessthanwhatisspecifiedinthedatasheet.ForCFBamplifiers:Thisisthefrequencyatwhichtheopenlooptransimpedancemagnitudeplotis1kΩ(60dBinsomedatasheets).2ndPloe:Thisisthefrequencyatwhichtheopenloopphaseis-135.ComparethisnumberwiththecalculatedfnoiseandensurefnoiseislessthanCF:IfthevalueislessthanthevalueenteredforCstray,thisboxturnsredwithyellowtextindicatingthatitwillnotbepossibletorealizethesignalBWshown.Toremainwithinreality,enteratleast0.2pFintheCstrayboxandenteratleastthesamenumberintheCminsomecasesBWsignalwillbelimitedbythestraycapacitanceofthefeedbackresistorandthestraycapacitanceofthePCB.InthesecasestheturnslightredwithblacktextindicatingthatsignalbandwidthislimitedbythestraycapacitanceacrossRF,notbytheamplifier.AmpType:Clickonthecellandselectatypefromthedropdownmenu.RIN,fCRandIBIAS:ReadthenotesthatpopupwhenyouhoveroverEnternumbersinthegreenboxesonlyfromdatasheets.Everythingelseiscalculated.Allthesheetsareprotectedtoavoidaccidentalerasures.Youcanonlyenterdatainthegreenboxes.Nopassword.Youcanunprotectifyouwanttoseetheequations.Thesheetisdividedinto4horizontalsections:Topleftsectionisforenetringsystemvariables,toprightisforenteringpartsspecs.NextsectionshowsthescematicsoftheTIAandmaxpossibleBandwidthwithworstSNRcalculationsforit.NextSectionshowsfrequencyresponseontheleftandpulseresponseontheYouareconfiguringtheTIAforitsmaximumpossiblesignalbandwidthwhenCC-setC-mintheTIAcouldoscillate.YoucanincreaseC-setaboveCIfthevalueislessthanthevalueenteredfor,thisboxturnsredwithyellowtextindicatingthatitwillnotbepossibletorealizethesignalBWshown.Toremainwithinreality,enterCstrayboxandenteratleastCminbox.NotethatinwillbelimitedbythestraycapacitanceofthefeedbackresistorandthestraycapacitanceofthePCB.InthesecasestheCFboxturnslightredwithblacktextindicatingthatsignalbandwidthislimitedbythestray,notbytheamplifier.Clickonthecellandselectatypefromthedrop-ReadthenotesthatpopupwhenyouhoverovertheTIAforitsmaximumpossiblesignalbandwidthwhenC-set=C-min.IfmintheTIAcouldoscillate.setaboveC-mintoadjustPartSpecsfromdatasheetADA4817ADA4891AD8045AD8011ADA4350ADA4932AD8099AmpTypeOp-AmpVFBOp-AmpVFBOp-AmpVFBOp-AmpCFBOp-AmpVFBDiff-AmpVFBOp-AmpVFBPeakInputCurrent:50μACd(pF)0.13.22.350.52CPHOTODIODE10pFCcm(pF)1.31.31Rincm(kΩ)500030004501100010000Rindiff(kΩ)9000.128160004RF:1kWfcr(MHz)380105350831905003800PeakOutput:50mV2ndpole(MHz)Vnoise(nV/Hz)493253.60.95Inoise(pA/Hz)0.00250350.000512.6Cstray:0.25pFIbias/osmax(μA)0.0000010.000056.61500.213Temp:25CVosmax(mV)2101.463.12.20.5Cfmin(pF)2.405.292.500.003.991.990.68MaxBW(MHz)66.1930.0663.5783.0039.9179.81235.11fpole(MHz)11.538.6111.55114.068.3812.7414.55Op-A