7421TTL4输入端双与门

TLF635654LS21DM54LS21DM74LS21Dual4-InputANDGatesJune 198954LS21DM54LS21DM74LS21Dual 4-Input AND GatesGeneral DescriptionThis device contains two independent gates each of whichperforms the logic AND functionFeaturesY Alternate MilitaryAerospacedevice (54LS21) is avail-able Contact a National Semiconductor Sales OfficeDistributor for specificationsConnection DiagramDual-In-Line PackageTLF6356– 1Order Number 54LS21DMQB 54LS21FMQB 54LS21LMQBDM54LS21J DM54LS21W DM74LS21Mor DM74LS21NSee NS Package Number E20AJ14AM14A N14A or W14BFunction TableY e ABCDInputsOutputABCDYXXXLLXXLXLXLXXLLXXXLHHHHHH e High Logic LevelL e Low Logic LevelX e Either Low or High Logic LevelC1995 NationalSemiconductorCorporationRRD-B30M105Printed in U S AAbsolute Maximum Ratings (Note)If MilitaryAerospacespecified devices are requiredpleasecontacttheNationalSemiconductorSalesOfficeDistributors for availability and specificationsSupply Voltage7VInput Voltage7VOperating Free Air Temperature RangeDM54LS and 54LSb55C to a125CDM74LS0C to a70CStorage Temperature Rangeb65C to a150CNoteThe ‘‘Absolute Maximum Ratings’’are those valuesbeyond which the safety of the device cannot be guaran-teedThe deviceshouldnot be operatedat theselimitsTheparametricvalues definedin the ‘‘ElectricalCharacteristics’’table are not guaranteedat the absolute maximum ratingsThe ‘‘RecommendedOperatingConditions’’table will definethe conditionsfor actual device operationRecommended Operating ConditionsSymbolParameterDM54LS21DM74LS21UnitsMinNomMaxMinNomMaxVCCSupply Voltage455554755525VVIHHigh Level Input Voltage22VVILLow Level Input Voltage0708VIOHHigh Level Output Currentb04b04mAIOLLow Level Output Current48mATAFree Air Operating Temperatureb55125070CElectrical Characteri...