52football：
1。2输入、输出延迟时间Thepropagationdelaycouldbecatalogedasturn-onandturn-offdelaytimes.Theturn-onpropagationdelayfrominputtooutput,td1,isdefinedastheperiodfrominputhighto10%ofoutputrail-to-railleveltosupplysourceVdd,whileTheturn-offpropagationdelayfrominputtooutput,td2,isdefinedastheperiodfrominputlowto90%ofoutputrail-to-railleveltosupplysourceVdd,bothonEnableactive,asshowninFig.1.Ontheotherhand,theenableonpropagationdelayfromenablesignaltooutput,td3,isdefinedastheperiodfromEnablehighto10%ofoutputrail-to-railleveltosupplysourceVdd,whiletheenableoffpropagationdelayfromenablesignaltooutput,td4,isdefinedastheperiodfromEnablelowto90%ofoutputrail-to-railleveltosupplysourceVdd,bothoninputactive,asshowninFig.2 ThepropagationdelaytimeisthefunctionofinputsignalamplitudeVin,supplyvoltageVdd,andoperatingtemperature.Littlecanbedonetolowerthedelayexceptforkeepingthedevicetemperaturelow.Needtonotethatslowrisinginputsignalscangivetheappearanceoflongdelaytimes.Thiscomesfromthefactthatthetrippointoftheinput(about1.5V)ofSchmitttriggerinthedrivercanoftenbehigherthanthe10%pointinthewaveform.