LM555 Timer (Rev. D) - TI.com

1 ProductFolderSample &BuyTechnicalDocumentsTools &SoftwareSupport &CommunityLM555 SNAS548D FEBRUARY2000 REVISEDJANUARY2015LM555 Timer1 Features3 DescriptionThe LM555is a highlystabledevicefor generating1 DirectReplacementfor SE555/NE555accuratetimedelaysor TimingfromMicrosecondsthroughHourstermin alsare providedfor triggeringor resettingif Operatesin BothAstableand the time delaymodeof operation,the timeis preciselycontrolledby one externalresistorand a stableoperationas an oscillator,the OutputCan Sourceor Sink200 mAfree runningfrequencyand dutycycleare accurately Outputand SupplyTTL circuitmaybe triggeredand reseton Cfallingwaveforms,and the outputcircuitcan source NormallyOn and NormallyOff Outputor sink up to 200 mA or driveTTL circuits. Availablein 8-pinVSSOPP ackageDeviceInformation(1)2 ApplicationsPARTNUMBERPACKAGEBODYSIZE(NO M) PrecisionTimingSOIC(8) PulseGenerationLM555 PDIP(8) (8) SequentialTiming TimeDelayGeneration(1) For all availablepackages,see the orderableaddendumatthe end of the datasheet.

2 PulseWidthModulation PulsePositionModulation LinearRampGeneratorSchematicDiagram1An IMPORTANTNOTICEat the end of this datasheetaddressesavailability,warranty, changes,use in safety-criticalapplications,intellectual propertymattersand FEBRUARY2000 Applicationand Pin Configurationand Deviceand Mechanical,Packaging,and RevisionHistoryChangesfromRevisionC (March2013)to RevisionDPage AddedPinConfigurationandFunctionssection ,ESDR atingstable,FeatureDescriptionsection,De viceFunctionalModes,ApplicationandImplem entationsection,PowerSupplyRecommendatio nssection,Layoutsection,DeviceandDocumen tationSupportsection,andMechanical,Packa ging, (March2013)to RevisionCPage Changedlayoutof NationalDataSheetto TI 2000 2015,TexasInstrumentsIncorporatedProduct FolderLinks: LM555 RRRGNDTRIGGEROUTPUTRESET1234+VCCDISCHARG ETHRESHOLDCONTROLVOLTAGE8765 COMPAR-ATORCOMPAR-ATORFLIP FLOPOUTPUT STAGEVREF (INT) FEBRUARY2000 REVISEDJANUARY20155 Pin Configurationand FunctionsD, P, and DGKP ackages8-PinPDIP,SOIC,and VSSOPTop ViewPin thresholdand determinesthe pulsewidthof the externalvoltageappliedto this pin can also be usedto modulatethe outputwaveformDischargeOpencollectoroutp utwhichdischargesa capacitorbetweenintervals(in phasewith output).

3 7 IIt togglesthe outputfromhigh to low whenvoltagereaches2/3 of the supplyvoltage1 GNDOG roundreferencevoltage3 OutputOOutputdrivenwaveformResetNegative pulseappliedto this pin to disableor resetthe usedfor reset4 Ipurposes,it shouldbe connectedto VCCto avoidfalsetriggeringThresholdComparesthe voltageappliedto the terminalwith a referencevoltageof 2/3 voltageappliedto this terminalis responsiblefor the set stateof the flip-flopTriggerResponsiblefor transitionof the flip-flopfromset to outputof the timerdepends2 Ion the amplitudeof the externaltriggerpulseappliedto this pin8V+ISupplyvoltagewith respectto GNDC opyright 2000 2015,TexasInstrumentsIncorporatedSubmitD ocumentationFeedback3 ProductFolderLinks:LM555LM555 SNAS548D FEBRUARY2000 (unlessotherwisenoted)(1)(2)MINMAXUNITLM 555CM,LM555CN(4)1180mWPowerDissipation(3 ) LM555 CMM613mWPDIPP ackageSoldering(10 Seconds)260 CSolderingVaporPhase(60 Seconds)215 CSmallOutlinePackages(SOICandInformation VSSOP)Infrared(15 Seconds)220 CStoragetemperature,Tstg 65150 C(1)StressesbeyondthoselistedunderAbsolu teMaximumRatingsmay causepermanentdamageto the stressratingsonly,whichdo not implyfunctionaloperationof the deviceat theseor any otherconditionsbeyondthoseindicatedunder RecommendedOperatingConditions.

4 Exposureto absolute-maximum-ratedconditionsfor extendedperiodsmay affectdevicereliability.(2)If Military/Aerospacespecifieddevicesare required,pleasecontactthe TI SalesOffice/Distributorsfor availabilityand specifications.(3)For operatingat elevatedtemperaturesthe devicemustbe deratedabove25 C basedon a 150 C maximumjunctiontemperatureand athermalresistanceof 106 C/W(PDIP),170 C/W(S0IC-8),and 204 C/W(VSSOP)junctionto ambient.(4)Referto RETS555 Xdrawingof militaryLM555 Hand LM555 Jversionsfor (ESD)ElectrostaticdischargeHuman-bodymod el(HBM),per ANSI/ESDA/JEDECJS-001(1) 500(2)V(1)JEDEC documentJEP155statesthat 500-VHBM allowssafe manufacturingwith a standardESDcontrolprocess.(2)The ESDinformationlistedis for the (unlessotherwisenoted)MINMAXUNITS upplyVoltage18 VTemperature,TA070 COperatingjunctiontemperature,TJ70 (1)PDIPSOICVSSOPUNIT8 PINSR JAJunction-to-ambientthermalresistance10 6170204 C/W(1)For moreinformationabouttraditionaland new thermalmetrics,see theICPackageThermalMetricsapplicationrep ort, 2000 2015, FEBRUARY2000 (TA= 25 C, VCC= 5 V to 15 V, unlessotherwisespecified)(1)(2) 5 V, RL= 36mAVCC= 15 V, RL= 1015(LowState)(3)TimingError,MonostableI nitialAccuracy1 %Drift with TemperatureRA= 1 k to 100 k ,50ppm/ CC = F,(4) %Drift with %VTimingError, with TemperatureRA, RB=1 k to 100 k ,150ppm/ CC = F,(4) with VCCT riggerVoltageVCC= 15 V5 VVCC= 5 (5) AControlVoltageLevelVCC= 15 V91011 VVCC= 5 7 LeakageOutputHigh1100nAPin 7 Sat(6)

5 OutputLowVCC= 15 V, I7= 15 mA180mVOutputLowVCC= V, I7= mA80200mVOutputVoltageDrop(Low)VCC= 15 VISINK= 10 50 100 200 5 VISINK= 8 mAVISINK= 5 (1)All voltagesare measuredwith respectto the groundpin, unlessotherwisespecified.(2)AbsoluteMaxi mumRatingsindicatelimitsbeyondwhichdamag eto the devicemay whichthe deviceis functional,but do not and ACelectricalspecificationsunderparticula rtest assumesthat the deviceis withintheRecommendedOperatingConditions. Specificationsare not ensuredfor parameterswhereno limit is given,however,the typicalvalueis a goodindicationof deviceperformance.(3)Supplycurrentwhenou tputhigh typically1 mA less at VCC= 5 V.(4)Testedat VCC= 5 V and VCC= 15 V.(5)This will determinethe maximumvalueof RA+ RBfor 15 V maximumtotal (RA+ RB) is 20 M .(6)No protectionagainstexcessivepin 7 currentis necessaryprovidingthe packagedissipationratingwill not be 2000 2015,TexasInstrumentsIncorporatedSubmitD ocumentationFeedback5 ProductFolderLinks:LM555LM555 SNAS548D FEBRUARY2000 (continued)(TA= 25 C, VCC= 5 V to 15 V, unlessotherwisespecified)(1)(2)PARAMETER TESTCONDITIONSMINTYPMAXUNITO utputVoltageDrop(High)ISOURCE= 200 mA, VCC= 15 100 mA, VCC= 15 5 Output100nsFall Timeof SupplyCurrentvs.

6 SupplyVoltageFigure1. MinimumPulseWidthRequiredFor TriggeringFigure4. LowOutputVoltagevs. OutputSinkCurrentFigure3. HighOutputVoltagevs. OutputSourceCurrent6 SubmitDocumentationFeedbackCopyright 2000 2015, FEBRUARY2000 REVISEDJANUARY2015 TypicalCharacteristics(continued)Figure6 . LowOutputVoltagevs. OutputSinkCurrentFigure5. LowOutputVoltagevs. OutputSinkCurrentFigure8. OutputPropagationDelayvs. VoltageLevelofFigure7. OutputPropagationDelayvs. VoltageLevelofTriggerPulseTriggerPulseFi gure10. DischargeTransistor(Pin 7) Voltagevs. SinkFigure9. DischargeTransistor(Pin 7) Voltagevs. SinkCurrentCurrentCopyright 2000 2015,TexasInstrumentsIncorporatedSubmitD ocumentationFeedback7 ProductFolderLinks: LM555 COMPARATORTRIGGERFLIP FLOPCOMPARATORRESET+VccDISCHARGETHRESHOL DVref(int)OUTPUTSTAGECONTROLVOLTAGEOUTPU TLM555 SNAS548D FEBRUARY2000 LM555is a highlystabledevicefor generatingaccuratetimedelaysor triggeringor resettingif the time delaymodeof operation,the time is preciselycontrolledby one externalresistorand astableoperationas an oscillator,the free runningfrequencyand dutycycleare accuratelycontrolledwith two externalresistorsand one circuitmaybe triggeredandreseton fallingwaveforms,and the outputcircuitcan sourceor sink up to 200mAor driverTTL availablein 8-pinPDIP,SOIC,and VSSOP packagesand is a directreplacementfor SE555 SE555/NE555 The LM555timeris a directreplacementfor SE555and is pin-to-pincompatibleso that no schematicor layoutchangesare LM555comein an 8-pinPDIP,SOIC.

7 And LM555has the abilityto havetimingparametersfromthe microsecondsrangeto timedelayofthe systemcan be determinedby the timeconstantof the R and C valueusedfor eitherthe nomographis availablefor easydeterminationof R and C valuesfor varioustime BothAstableand MonostableModeThe LM555can operatein bothastableand monostablemodedependingon the applicationrequirements. Monostablemode:The LM555timeracts as a one-shot pulsebeingswhenthe LM555timerreceivesa signalat the triggerinputthat falls belowa 1/3 of the widthof the outputpulseis determinedby the timeconstantof an RC outputpulseendswhenthe voltageon the8 SubmitDocumentationFeedbackCopyright 2000 2015, FEBRUARY2000 REVISEDJANUARY2015 FeatureDescription(continued)capacitoreq uals2/3 of the outputpulsewidthcan be extendedor shorteneddependingon the applicationby adjustingthe R and C values.

8 Astable(free-running)mode:The LM555timercan operateas an oscillatorand puts out a continuousstreamof rectangularpulseshavinga frequencyof the pulsestreamdependson the valuesof RA, RB, and this modeof operation,the timerfunctionsas a one-shot(Figure11). The externalcapacitoris initiallyhelddischargedby a transistorinsidethe a negativetriggerpulseof less than1/3 VCCtopin 2, the flip-flopis set whichbothreleasesthe shortcircuitacrossthe capacitorand drivesthe MonostableThe voltageacrossthe capacitorthenincreasesexponentiallyfor a periodof t = RAC, at the end of whichtimethe voltageequals2/3 VCC. The comparatorthenresetsthe flip-flopwhichin turn dischargesthe capacitorand drivesthe outputto its low showsthe waveformsgeneratedin this modeof chargeand the thresholdlevelof the comparatorare bothdirectlyproportionalto supplyvoltage,the timingintervalis independentof 5 VTop Trace:Input5 :Output5 k BottomTrace:CapacitorVoltage2 = FFigure12.

9 MonostableWaveformsDuringthe timingcyclewhenthe outputis high,the furtherapplicationof a triggerpulsewill not effectthe circuitso longas the triggerinputis returnedhighat least10 s beforethe end of the be resetduringthis time by the applicationof a negativepulseto the resetterminal(pin 4). The outputwill thenremainin the low stateuntil a triggerpulseis resetfunctionis not in use, TI recommendsconnectingthe Resetpin to VCCto avoidany 2000 2015,TexasInstrumentsIncorporatedSubmitD ocumentationFeedback9 ProductFolderLinks:LM555LM555 SNAS548D FEBRUARY2000 (continued)Figure13 is a nomographfor easydeterminationof R, C valuesfor varioustime the circuitis connectedas shownin Figure14 (pins2 and 6 connected)it will triggeritselfand free run as externalcapacitorchargesthroughRA+ RBand dischargesthroughRB.

10 Thusthe dutycyclemay be preciselyset by the ratioof thesetwo AstableIn this modeof operation,the capacitorchargesand dischargesbetween1/3 VCCand 2/3 VCC. As in thetriggeredmode,the chargeand dischargetimes,and thereforethe frequencyare independentof the showsthe waveformsgeneratedin this modeof 2000 2015, FEBRUARY2000 REVISEDJANUARY2015 DeviceFunctionalModes(continued)VCC= 5 VTop Trace:Output5 20 :CapacitorVoltage1 k RB= 3 k C = FFigure15. AstableWaveformsThe chargetime (outputhigh)is givenby:t1= (RA+ RB) C(1)And the dischargetime (outputlow) by:t2= (RB) C(2)Thusthe total periodis:T = t1+ t2= (RA+2RB) C(3)The frequencyof oscillationis:(4)Figure16 may be usedfor quickdeterminationof theseRC duty cycleis:(5)Figure16. FreeRunningFrequencyCopyright 2000 2015,TexasInstrumentsIncorporatedSubmitD ocumentationFeedback11 ProductFolderLinks.