74LS74参考手册.pdf

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1、DFlip-FlopswithPreset,ClearandComplementaryOutputs54LS74/DM54LS74A/DM74LS74ADualPositive-Edge-TriggeredJune198954LS74/DM54LS74A/DM74LS74ADualPositive-Edge-TriggeredDFlip-FlopswithPreset,ClearandComplementaryOutputsGeneralDescriptionThisdevicecontainstwoindependentpositive-

2、edge-trig-violated.AlowlogiclevelonthepresetorclearinputswillgeredDflip-flopswithcomplementaryoutputs.Theinforma-setorresettheoutputsregardlessofthelogiclevelsofthetionontheDinputisacceptedbytheflip-flopsontheposi-otherinputs.tivegoingedgeoftheclockpulse.Thetriggeringoccur

3、satavoltagelevelandisnotdirectlyrelatedtothetransitiontimeFeaturesoftherisingedgeoftheclock.ThedataontheDinputmayYAlternatemilitary/aerospacedevice(54LS74)isavail-bechangedwhiletheclockisloworhighwithoutaffectingable.ContactaNationalSemiconductorSalesOffice/theoutputsaslon

4、gasthedatasetupandholdtimesarenotDistributorforspecifications.ConnectionDiagramDual-In-LinePackageTL/F/6373±1OrderNumber54LS74DMQB,54LS74FMQB,54LS74LMQB,DM54LS74AJ,DM54LS74AW,DM74LS74AMorDM74LS74ANSeeNSPackageNumberE20A,J14A,M14A,N14AorW14BFunctionTableInputsOutputsPRCLRCL

5、KDQQLHXXHLHLXXLHLLXXH*H*HHuHHLHHuLLHHHLXQ0Q0HeHighLogicLevelXeEitherLoworHighLogicLevelLeLowLogicLeveluePositive-goingTransition*eThisconfigurationisnonstable;thatis,itwillnotpersistwheneitherthepresetand/orclearinputsreturntotheirinactive(high)level.Q0eTheoutputlogiclevel

6、ofQbeforetheindicatedinputconditionswereestablished.C1995NationalSemiconductorCorporationTL/F/6373RRD-B30M105/PrintedinU.S.A.AbsoluteMaximumRatings(Note)IfMilitary/Aerospacespecifieddevicesarerequired,Note:The``AbsoluteMaximumRatings''arethosevaluespleasecontacttheNational

7、SemiconductorSalesbeyondwhichthesafetyofthedevicecannotbeguaran-Office/Distributorsforavailabilityandspecifications.teed.Thedeviceshouldnotbeoperatedattheselimits.TheSupplyVoltage7Vparametricvaluesdefinedinthe``ElectricalCharacteristics''tablearenotguaranteedattheabsolutem

8、aximumratings.InputVoltage7VThe``RecommendedOperatingConditions''tablewilldefineOperating