1、June 1989 count pulses are applied to input A and the outputs are asdescribed in the appropriate truth A symmetrical di-vide-by-ten count can be obtained from the LS90 countersby connecting the Q output to the A input and applying theinput count to the B input which gives a divide-by-ten squareDTypi

2、cal power dissipation 45 Count frequency 42 the B input is connected to the A(Dual-In-Line Packages)Order D74LS90 D74LS90NSee Package 14A N14AC1995 National Semiconductor Corporationin (Note) deviceshouldnotoperatedatparametricvaluesdefinedinElectricalCharacteristics guaranteedat RecommendedOperatin

3、gConditionstablewill conditionsfor Supply VoltageStorage Temperature Rangeb65 Cto a150 CD74LS90UnitsParameterSupply Voltage52V00Clock Frequency (Note 2)PulseWidth (Note 1)00BnsnsPulseWidth (Note 2)BResetnsnsC70RL e 2 kX TA e 25 C and VCCRL e 2 kX TA e 25 C and VCCeeover recommended operating free ai

4、r temperature range (unless otherwise noted)inUnitsInput Clamp VoltageeeI e b18 bIOHeOLLowLevel OutputVoltageeeVeResetIV eI2 over recommended operating free air temperature range (unless otherwise noted) (Continued)ParameterUnitseV eResetIAABeV eResetbIShort CircuitCCe ax (Note 2)CCe ax (Note 3)Outp

5、ut CurrentSupply Current915All typicals are at VCCeNot more than one output should be shorted at aand the duration should not exceed oneboth RO inputs grounded following momentary connection toand all other inputsQA outputs are tested at IOL e ax plus the limit value of IIL for the BThis permits dri

6、ving the B input while maintaining full fan-outat VCC e 5V and TA e 25 C (See Section 1 for Test Waveforms and Output Load)Le 2kXParameterLe 15 pFaxLe 50 pFaxUnitsPropagation Delay TimeLow toHigh Level Output1620Propagation Delay TimeHightoLow Level OutputPropagation Delay TimeLow toHigh Level Outpu

7、tPropagation Delay TimeHightoLow Level OutputPropagation Delay TimeLow toHigh Level OutputPropagation Delay TimeHightoLow Level OutputPropagation Delay TimeLow toHigh Level OutputPropagation Delay TimeHightoLow Level OutputPropagation Delay TimeLow toHigh Level OutputPropagation Delay TimeHightoLow

8、Level OutputPropagation Delay TimeLow toHigh Level OutputPropagation Delay TimeHightoLow Level OutputPropagation Delay TimeHightoLow Level Output3ParameterUnitsSupply Voltage2V00Clock Frequency (Note 2)Pulse Width (Note 1)00BnsnsPulse Width (Note 2)BResetnsnsC70RL e 2 kX TA e 25 C and VCCRL e 2 kX T

9、A e 25 C and VCCeeover recommended operating free air temperature range (unless otherwise noted)inUnitsInput Clamp VoltageeeI e b18 bIOHeOLLowLevel OutputVoltageeeVeResetIAV eIBIIHReset20V eI4 over recommended operating free air temperature range (unless otherwise noted) (Continued)ParameterUnitseV

10、eResetIShort CircuitCCe ax (Note 2)CCe ax (Note 3)Output CurrentSupply Current915All typicals are at VCCeNot more than one output should be shorted at aand the duration should not exceed oneboth RO inputs grounded following momentary connection toand all other inputsQA outputs are tested at IOL e ma

11、x plus the limit value of IIL for the BThis permits driving the B input while maintaining full fan-outat VCC e 5V and TA e 25 C (See Section 1 for Test Waveforms and Output Load)Le 2kXParameterUnitsPropagation Delay TimeLow toHigh Level Output1620Propagation Delay TimeHightoLow Level OutputPropagati

12、on Delay TimeLow toHigh Level OutputPropagation Delay TimeHightoLow Level OutputPropagation Delay TimeLow toHigh Level OutputPropagation Delay TimeHightoLow Level OutputPropagation Delay TimeLow toHigh Level OutputPropagation Delay TimeHightoLow Level OutputPropagation Delay TimeLow toHigh Level Out

13、putPropagation Delay TimeHightoLow Level OutputPropagation Delay TimeHightoLow Level Output5LHLLLLLLLHLLLLHLHLLHHLLHHLLHLLHLLLHLLLHHLLHLHLHHLHLLLHOutputR0(1) R0(2) R9(1) R9(2) D C B ABHHXXLHHXLLXHXLXL01LHLHLHH2LL3LLHLXXLXL4LLXL5LLHLXX6L7LHL8LS939LLHLTruthTableLReset InputsOutputLHLR0(1)R0(2)LHLHLHXL

14、LLLLHXNoteNoteNoteL e LowX e Dont6LS90The J and K inputs shown without connection are for reference only and are functionally at a high7 14-Lead Small Outline olded Package ()Order D74LS90 D74LS93 Package 14A9sr einches (millimeters) (Continued)tnuoCyraniBdnaedaceD39SL47D09SL4714-Lead olded Dual-In-

15、Line Package (N)Order D74LS90N D74LS93N Package N14ADLIFE POLICYNATIONALS CRITICAL IN LIFE DEVICES usedLife support devices or systems are devices orA critical component is any component of a lifesupport device or system whose failure to perform canbe reasonably expected to cause the failure of the lifesystemsinto thefailure to(a) are intended for surgi