常用芯片资料——DM74121

June1989Revised November1999SEMICONDUCTOR TMDM74121One-Shot withClear andComplementary OutputsGeneralDescription FeaturesTheDM74121is amonostable multivibratorfeaturing bothTriggered fromactive-HIGH transitionor active-LOWpositive andnegative edgetriggering withcomplementary transitioninputsoutputs.An internal2kC timingresistor isprovided fordesign Variablepulse widthfrom30ns to28secondsconvenience minimizingcomponent countand layoutJitterfree Schmitt-trigger inputproblems,this devicecan beused witha singleexternalExcellent noiseimmunity typically

1.2Vcapacitor.Inputs Aare active-LOW triggertransition inputsStablepulse widthup to90%duty cycleandinput Bis andactive-HIGH transitionSchmitt-triggerinput thatallows jitter-free triggeringfrom inputswith transitionTTL,DTL compatibleratesas slowas1volt/second.A highimmunity toVcc noiseCompensated forVcc andtemperature variationsoftypically

1.5V isalso providedby internalcircuitry at theInput clampdiodesinput stage.lb obtainoptimum andtrouble freeoperation pleasereadoperating rulesand one-shot applicationnotes carefullyandobserve recommendations.Ordering Code:Order NumberPackage NumberPackage DescriptionConnectionDiagram FunctionTableInputs OutputsREXTZA1A2B QQL XH LHX LH LHX X L LHH HXLHH IH-n_u-1H H_n__LrJ]H-TL-LTL Xt-rL-LTX Lt-TLU-DM74121N N14A14-Lead PlasticDual-ln-Line PackagePDIP,JEDEC MS-001,

0.300WideFunctional Descriptionfew nano-seconds to28seconds bychoosing appropriateRxand Cxcombinations.There arethree triggerinputs fromtheThe basicoutput pulse width isdetermined byselection ofandevice,two negativeedge-triggering Ainputs,one positiveinternal resistor RINTor an external resistor Rx and capacitoredge Schmitt-triggering Binput.Cx.Once triggeredthe output pulsewidth is independentoffurther transitionsof theinputs andis function of thetimingcomponents.Pulse widthcan varyfrom aH=HIGHLogicLevel f=PositiveGoingTransitionL=LOWLogicLevel|=NegativeGoingTransitionX=CanBeEitherLOWorHIGH_n_=APositivePulse-u-=ANegativePulsewOperating Rules寸zw

1.lbuse theinternal2kQ timingresistor,connect theRINTpin三TA・25tVee=

5.0V;a toVcc-sees.=R=50K

2.An externalresistorRxor theinternalresistor2kQ andK2S:anexternalcapacitor Cxare required for proper=25Koperation.The valueof Cxmay varyfrom0to anynecessary value.For smalltime constantsuse high-qualitymica,glass,polypropylene,polycarbonate,or polystyrenecapacitors.For largetime constantsuse solidtantalum orspecialaluminum capacitors.If thetiming capacitorshaveleakages approaching100nA orif straycapacitance from10either terminalto groundis greaterthan50pF thetiming10equations maynot representthe pulsewidth thedevice CfXTpFgenerates.FIGURE

1.

3.The pulsewidthisessentially determinedby externaltimingcomponents Rxand Cx.For Cx1000pF seeRxDvCC-VAr——PIN11»Figure1design curveson twasfunctionoftimingcomponents value.For Cx1000pF the output isdefinedCxHFas:PIN10旷、~xFIGURE

2.where[Rx isin Kilo-ohm][Cxis inpico Farad][tw isin nanosecond]工[K

0.7]

4.If Cxis anelectrolytic capacitora switchingdiode isoften送至requiredforstandard TTLone-shots toprevent high上inverse leakagecurrent Figure

2.

5.Output pulsewidth versus Vcc andoperationtemperatures:Figure3depicts therelationship betweenpulsewidth variationversusVcc.Figure4depicts pulse-io4455556width variationversus ambienttemperature.*CC V

6.The Kcoefficient isnot aconstant,but variesas afunctionof thetiming capacitorCx.Figure5details thisFIGURE

3.characteristic.io

7.Under anyoperating conditionCx andRx mustbe keptasclose tothe one-shot devicepins aspossible tominimizestray capacitance,toreduce noisepick-up,and toreduceI5X Rand Ldi/dt voltagedeveloped alongtheir connectingpaths.If thelead lengthfrom Cxto pins10and11isgreater than3cm,for example,theoutputpulse widthmightbe quitedifferent fromvalues predictedfrom theappropriateequations.A non-inductive andlowcapacitivepath is necessary toensure completedischarge ofCx in-10each cycleof itsoperation so that theoutputpulsewidth-60-300306Q90120150will beaccurate.AMBIENT TEMPERATURE°C

8.Vcc and ground wiringshould conformto goodhigh-FIGURE

4.frequency standardsand practicessothatswitchingtransients onthe Vccandgroundreturn leadsdo not100cause interactionbetweenone-shots.A

0.01pF to

0.10pFbypass capacitordisk ceramicor monolithictype fromVccto groundisnecessaryon eachdevice.Furthermore,the bypasscapacitor shouldbe locatedas closeto theVcc-pin asspace permits.For furtherdetailed devicecharacteristics andoutputperformance pleaserefer tothe one-shot applicationnote,AN-

366.10pF

0.

2.

4.

6.

81.

01.

2141.6•,KCOEFFICIENTFIGURE

5.DM7Absolute MaximumRatings Notei4121Supply Voltage7VNote1:TheAbsoluteMaximumRatingsarethosevaluesbeyondwhichInput Voltage

5.5V thesafetyofthedevicecannotbeguaranteed.ThedeviceshouldnotbeOperating FreeAir TemperatureRange0℃to+70℃篙面*attheselimits.TheparametricvaluesdefinedintheElectrical「口l dCharactensticstablesarenotguaranteedattheabsolutemaximumratings.Storage TemperatureRange-65℃to+150℃TheRecommendedOperatingConditionstablewilldefinetheconditionsforactualdeviceoperation.Recommended OperatingConditionsSymbol ParameterMin NomMax UnitsVccSupply Voltage

4.

7555.25VVT+Positive-Going InputThreshold Voltageat theA InputVcc=Min

1.42VVT-Negative-Going InputThreshold Voltageat theA InputVcc=Min

0.

81.4VVT+Positive-Going InputThreshold Voltageat theB InputVcc=Min

1.52VVT-Negative-Going InputThreshold VoltageattheB InputVcc=Min

0.

81.3VlOH HIGHLevel outputCurrent-

0.4mAlOL LOWLevel OutputCurrent16mAlw InputPulse WidthNote240nsdV/dt Rateof Riseor Fallof1V/sSchmidt InputB Note2dV/dt Rateof Riseor Fallof1V/psSchmidt InputA Note2REXT ExternalTiming ResistorNote

21.440kQExternal TimingCapacitance Note201000pFCEXT cc___DU DutyCycle Note2RT=2kQ67%RT=REXTM3X90TA FreeAir OperatingTemperature070℃Note2:TA=25℃andVcc=5VElectrical CharacteristicsoverrecommendedoperatingfreeairtemperaturerangeunlessotherwisenotedSymbolParameter Conditions Min TypNote3Max UnitsViInputClampVoltage VCC=Min,h=-12mA-

1.5VVOH HIGHLevelOutputVoltageVcc=Min,IOH=Max,VIL=Max,VIH=Min

2.

43.4VVOL LOWLevelOutputVoltageVcc—Mui,lOL-Max,VIH=Max,VIL=Min

0.

20.4VII InputCurrent@MaxInputVoltageVcc=Max,V|=

5.5V1mAIlH HIGHLevelVcc=Max,V|=

2.4V A1,A240pAInputCurrent B80hL LOWLevelVcc=Max,V|=

0.4V A1,A2-

1.6mAInputCurrent B-

3.2los ShortCircuitOutputCurrentVcc=MaxNote4-18-55mAicc SupplyCurrentvcc=Max Quiescent1325mATriggered2340Note3:AlltypicalsareatVcc=5V,TA=25℃.Note4:Notmorethanoneoutputshouldbeshortedatatime.w寸Switching CharacteristicszwAtVcc=5VandTA=25℃SeeTestWaveformsandOutputLoadSectionaFrom InputToOutputSymbol ParameterConditionsMinMax UnitstPLHPropagationDelayTime A1,A2toQ CEXT=80pFRlNTtO70nsLOW-to-HIGHLevelOutput VccCL-15pFRL=400QtPLH PropagationDelayTimeBto55nsLOW-to-HIGHLevelOutput QtPHLPropagationDelayTime A1,A2toQ80nsHIGH-to-LOWLevelOutputtPHL PropagationDelayTimeB65nsHIGH-to-LOWLevelOutput toQtWOUTOutputPulse A1,A2orBtoQ,QWidthUsingtheCEXT=80pFRlNTtoVcc70150nsInternalTimingResistorRL=400QCL=15pFc f\f-tWOUT OutputPulseWidthUsingZeroTimingA1,A2toQ,Q CEXT-0pFRlNTtoVCCCapacitanceRL=400Q50nsCL=15pFtWOUT OutputPulseA1,A2toQ,Q CEXT=100pFWidthUsingExternal RlNT=10kQ600800nsTimingResistor RL=400QCL=15pFA1,A2toQ,Q CEXT=1|iFRlNT=10kC68msRL=400QCL=15pFPhysical Dimensionsinches millimetersunless otherwisenoted Fairchilddoes notassume anyresponsibility Dforuse ofany circuitrydescribed,no circuitpatentlicenses areimplied andFairchild reservesthe rightat anytime withoutnotice tochange saidcircuitry andspecifications.MLIFE SUPPORTPOLICY7FAIRCHILDS PRODUCTSARE NOTAUTHORIZED FORUSE ASCRITICAL COMPONENTSIN LIFESUPPORT DEVICESORSYSTEMS WITHOUTTHE EXPRESSWRITTEN APPROVALOF THEPRESIDENT OFFAIRCHILD SEMICONDUCTORCORPORATION.As usedherein:

41.Life support devices or systems aredevices or systemswhich,a areintended forsurgical implantinto thebody,or1b supportor sustainlife,andcwhose failureto performwhenproperly usedin accordancewith instructionsfor useprovidedin thelabeling,can be reasonably expectedto2result ina significantinjury tothe user.OPTION

12.A criticalcomponent inany componentof1a lifesupport deviceorsystemwhose failureto

0.135x0005perform canbereasonablyexpected tocausethefailure ofthe lifesupportdeviceorsystem,or toaffect itsosafety oreffectiveness.necohof14-Lead PlasticDual-In-Line PackagePDIP,JEDEC MS-001,

0.300WidePackage NumberN14Aw。