LM202.4V,10µA,SC70,microSMDTemperatureSensorOctober1999
LM20
2.4V,10µA,SC70,microSMDTemperatureSensor
GeneralDescription
TheLM20isaprecisionanalogoutputCMOSintegrated-circuittemperaturesensorthatoperatesovera−55˚Cto+130˚Ctemperaturerange.Thepowersupplyop-eratingrangeis+2.4Vto+5.5V.ThetransferfunctionofLM20ispredominatelylinear,yethasaslightpredictableparaboliccurvature.TheaccuracyoftheLM20whenspeci-fiedtoaparabolictransferfunctionis±1.5˚Catanambienttemperatureof+30˚C.Thetemperatureerrorincreaseslin-earlyandreachesamaximumof±2.5˚Catthetemperaturerangeextremes.Thetemperaturerangeisaffectedbythepowersupplyvoltage.Atapowersupplyvoltageof2.7Vto5.5Vthetemperaturerangeextremesare+130˚Cand−55˚C.Decreasingthepowersupplyvoltageto2.4Vchangesthenegativeextremeto−30˚C,whilethepositiveremainsat+130˚C.
TheLM20’squiescentcurrentislessthan10µA.Therefore,self-heatingislessthan0.02˚Cinstillair.Shutdowncapabil-ityfortheLM20isintrinsicbecauseitsinherentlowpowerconsumptionallowsittobepowereddirectlyfromtheoutputofmanylogicgatesordoesnotnecessitateshutdownatall.
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BatteryManagementFAXMachinesPrintersHVAC
DiskDrivesAppliances
Features
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Ratedforfull−55˚Cto+130˚Crange
AvailableinanSC70andamicroSMDpackagePredictablecurvatureerror
Suitableforremoteapplications
KeySpecifications
nAccuracyat+30˚C
nAccuracyat+130˚C&−55˚CnPowerSupplyVoltageRangenCurrentDrainnNonlinearitynOutputImpedancenLoadRegulation
0µA +2.4Vto+5.5V10µA(max) ±0.4%(typ) 160Ω(max)−2.5mV(max) Applications nCellularPhonesnComputers nPowerSupplyModules TypicalApplication OutputVoltagevsTemperature DS100908-2 VO=(−3.88x10−6xT2)+(−1.15x10−2xT)+1.8639 or where: Tistemperature,andVOisthemeasuredoutputvoltageoftheLM20. DS100908-24 Full-RangeCelsius(Centigrade)TemperatureSensor(−55˚Cto+130˚C) OperatingfromaSingleLi-IonBatteryCell ©1999NationalSemiconductorCorporationDS100908www.national.com 元器件交易网www.cecb2b.com LM20TypicalApplication Temperature(T) +130˚C+100˚C+80˚C+30˚C (Continued)TypicalVO+303mV+675mV+919mV+1515mV Temperature(T) +25˚C0˚C−30˚C−40˚C−55˚C TypicalVO+1574mV+1863.9mV+2205mV+2318mV+2485mV ConnectionDiagrams SC70-5 microSMD DS100908-1 Note: -GND(pin2)maybegroundedorleftfloating.Foroptimumthermalconductivitytothepcboardgroundplanepin2shouldbegrounded.-NC(pin1)shouldbeleftfloatingorgrounded.Othersignaltracesshouldnotbeconnectedtothispin. DS100908-32 TopView SeeNSPackageNumberMAA05A Note: -Pinnumbersarereferencedtothepackagemarkingtextorientation.-ReferenceJEDECRegistrationMO-211,variationBA -Theactualphysicalplacementofpackagemarkingwillvaryslightlyfromparttopart.Thepackagemarkingwilldesignatethedatecodeandwillvaryconsiderably.Packagemarkingdoesnotcorrelatetodevicetypeinanyway. TopView SeeNSPackageNumberBPA04DDC OrderingInformation OrderNumberLM20BIM7LM20BIM7XLM20CIM7LM20CIM7XLM20SIBPLM20SIBPX TemperatureAccuracy Temperature Range−55˚Cto+130˚C−55˚Cto+130˚C−55˚Cto+130˚C−55˚Cto+130˚C−40˚Cto+125˚C−40˚Cto+125˚C NSPackageNumberMAA05AMAA05AMAA05AMAA05ABPA04DDCBPA04DDC DeviceMarkingT2BT2BT2CT2CDateCodeDateCode TransportMedia1000UnitsonTapeandReel3000UnitsonTapeandReel1000UnitsonTapeandReel3000UnitsonTapeandReel250UnitsonTapeandReel3000UnitsonTapeandReel ±2.5˚C±2.5˚C±5˚C±5˚C±3.5˚C±3.5˚C www.national.com2 元器件交易网www.cecb2b.com LM20AbsoluteMaximumRatings(Note1) SupplyVoltageOutputVoltage OutputCurrent InputCurrentatanypin(Note2)StorageTemperature MaximumJunctionTemperature(TJMAX)ESDSusceptibility(Note3):HumanBodyModelMachineModel +6.5Vto−0.2V(V++0.6V)to −0.6V10mA5mA −65˚Cto+150˚C +150˚C 2500V250V LeadTemperature SC-70Package(Note4):VaporPhase(60seconds)Infrared(15seconds) +215˚C+220˚C OperatingRatings(Note1) SpecifiedTemperatureRange:LM20B,LM20Cwith2.4V≤V+≤2.7VLM20B,LM20Cwith 2.7V≤V+≤5.5VLM20Swith 2.4V≤V+≤5.5VLM20Swith 2.7V≤V+≤5.5V SupplyVoltageRange(V+) ThermalResistance,θJA(Note5)SC-70 microSMD TMIN≤TA≤TMAX−30˚C≤TA≤+130˚C−55˚C≤TA≤+130˚C−30˚C≤TA≤+125˚C−40˚C≤TA≤+125˚C +2.4Vto+5.5V 415˚C/WTBD˚C/W ElectricalCharacteristics Unlessotherwisenoted,thesespecificationsapplyforV+=+2.7VDC.BoldfacelimitsapplyforTA=TJ=TMINtoTMAX;allotherlimitsTA=TJ=25˚C;Unlessotherwisenoted. Parameter Conditions Typical(Note6) LM20BLimits(Note7) TemperaturetoVoltageErrorVO=(−3.88x10−6xT2) +(−1.15x10−2xT)+1.8639V(Note8) TA=+25˚Cto+30˚CTA=+130˚CTA=+125˚CTA=+100˚CTA=+85˚CTA=+80˚CTA=0˚CTA=−30˚CTA=−40˚CTA=−55˚C OutputVoltageat0˚CVariancefromCurveNon-Linearity(Note9)SensorGain(TemperatureSensitivityorAverageSlope)toequation: VO=−11.77mV/˚CxT+1.860VOutputImpedanceLoadRegulation(Note10)LineRegulationQuiescentCurrent ChangeofQuiescentCurrentTemperatureCoefficientofQuiescentCurrentShutdownCurrent V+≤+0.8V 0.02 µA −20˚C≤TA≤+80˚C−30˚C≤TA≤+100˚C +1.8639 LM20CLimits(Note7) LM20SLimits(Note7) Units(Limit)˚C(max)˚C(max)˚C(max)˚C(max)˚C(max)˚C(max)˚C(max)˚C(min)˚C(max)˚C(max) V˚C% −11.4−12.2 −11.0−12.6 −11.0−12.6 mV/˚C(min)mV/˚C(max) ±1.5±2.5±2.5±2.2±2.1±2.0±1.9±2.2±2.3±2.5 ±1.0±0.4 −11.77 ±4.0±5.0±5.0±4.7±4.6±4.5±4.4±4.7±4.8±5.0 ±2.5±3.5±3.2±3.1±3.0±2.9±3.3±3.5 0µA≤IL≤+16µA(Notes11,12) 0µA≤IL≤+16µA(Notes11,12) +2.4V≤V+≤+5.0V+5.0V≤V≤+5.5V+2.4V≤V≤+5.5V+2.4V≤V≤+5.0V+2.4V≤V≤+5.5V ++++160−2.5+3.3+8.8 4.54.5+0.7−11 710 160−2.5+3.7+8.9710 160−2.5+3.7+8.9710 Ω(max)mV(max)mV/V(max)mV(max)µA(max)µA(max)µAnA/˚C 3www.national.com 元器件交易网www.cecb2b.com LM20ElectricalCharacteristics (Continued) Note1:AbsoluteMaximumRatingsindicatelimitsbeyondwhichdamagetothedevicemayoccur.OperatingRatingsindicateconditionsforwhichthedeviceisfunc-tional,butdonotguaranteespecificperformancelimits.Forguaranteedspecificationsandtestconditions,seetheElectricalCharacteristics.Theguaranteedspeci-ficationsapplyonlyforthetestconditionslisted.Someperformancecharacteristicsmaydegradewhenthedeviceisnotoperatedunderthelistedtestconditions.Note2:Whentheinputvoltage(VI)atanypinexceedspowersupplies(VI Note3:Thehumanbodymodelisa100pFcapacitordischargedthrougha1.5kΩresistorintoeachpin.Themachinemodelisa200pFcapacitordischargeddi-rectlyintoeachpin. Note4:SeeAN-450“SurfaceMountingMethodsandTheirEffectonProductReliability”orthesectiontitled“SurfaceMount”foundinanypost1986NationalSemi-conductorLinearDataBookforothermethodsofsolderingsurfacemountdevices. Note5:Thejunctiontoambientthermalresistance(θJA)isspecifiedwithoutaheatsinkinstillairusingtheprintedcircuitboardlayoutshowninFigure*NOTARGETFORfigNS1382*. Note6:TypicalsareatTJ=TA=25˚Candrepresentmostlikelyparametricnorm.Note7:LimitsareguaranteedtoNational’sAOQL(AverageOutgoingQualityLevel). Note8:Accuracyisdefinedastheerrorbetweenthemeasuredandcalculatedoutputvoltageatthespecifiedconditionsofvoltage,current,andtemperature(ex-pressedin˚C). Note9:Non-Linearityisdefinedasthedeviationofthecalculatedoutput-voltage-versus-temperaturecurvefromthebest-fitstraightline,overthetemperaturerangespecified. Note10:Regulationismeasuredatconstantjunctiontemperature,usingpulsetestingwithalowdutycycle.Changesinoutputduetoheatingeffectscanbecom-putedbymultiplyingtheinternaldissipationbythethermalresistance. Note11:NegativecurrentsareflowingintotheLM20.PositivecurrentsareflowingoutoftheLM20.UsingthisconventiontheLM20canatmostsink−1µAandsource+16µA. Note12:Loadregulationoroutputimpedancespecificationsapplyoverthesupplyvoltagerangeof+2.4Vto+5.5V. Note13:Lineregulationiscalculatedbysubtractingtheoutputvoltageatthehighestsupplyinputvoltagefromtheoutputvoltageatthelowestsupplyinputvoltage. TypicalPerformanceCharacteristics TemperatureErrorvsTemperature DS100908-25 PCBLayoutsUsedforThermalMeasurements DS100908-29 DS100908-30 a)Layoutusedfornoheatsinkmeasurements. b)Layoutusedformeasurementswithsmallheathink. FIGURE1.PCBLyoutsusedforthermalmeasurements. www.national.com4 元器件交易网www.cecb2b.com LM201.0LM20TransferFunction TheLM20’stransferfunctioncanbedescribedindifferentwayswithvaryinglevelsofprecision.Asimplelineartransferfunction,withgoodaccuracynear25˚C,is VO=−11.69mV/˚CxT+1.8663VOverthefulloperatingtemperaturerangeof−55˚Cto+130˚C,bestaccuracycanbeobtainedbyusingthepara-bolictransferfunction VO=(−3.88x10−6xT2)+(−1.15x10−2xT)+1.8639solvingforT: whereTisthemiddleofthetemperaturerangeofinterestandmisinV/˚C.ForexampleforthetemperaturerangeofTmin=−30toTmax=+100˚C: T=35˚Cand m=−11.77mV/˚C Theoffsetofthelineartransferfunctioncanbecalculatedusingthefollowingequation: b=(VOP(Tmax)+VOP(T)+mx(Tmax+T))/2, where: •VOP(Tmax)isthecalculatedoutputvoltageatTmaxusingtheparabolictransferfunctionforVO• Alineartransferfunctioncanbeusedoveralimitedtempera-turerangebycalculatingaslopeandoffsetthatgivebestre-sultsoverthatrange.Alineartransferfunctioncanbecalcu-latedfromtheparabolictransferfunctionoftheLM20.Theslopeofthelineartransferfunctioncanbecalculatedusingthefollowingequation: m=−7.76x10−6xT−0.0115, VOP(T)isthecalculatedoutputvoltageatTusingtheparabolictransferfunctionforVO. UsingthisprocedurethebestfitlineartransferfunctionformanypopulartemperaturerangeswascalculatedinFigure2.AsshowninFigure2theerrorthatisintroducedbythelin-eartransferfunctionincreaseswithwidertemperatureranges. TemperatureRangeTmin(˚C)−55−40−30-40−10+35+20 Tmax(˚C)+130+110+100+85+65+45+30 LinearEquation VO= −11.79mV/˚CxT+1.8528V−11.77mV/˚CxT+1.8577V−11.77mV/˚CxT+1.8605V−11.67mV/˚CxT+1.8583V−11.71mV/˚CxT+1.8641V−11.81mV/˚CxT+1.8701V−11.69mV/˚CxT+1.8663V MaximumDeviationofLinearEquationfromParabolicEquation (˚C) ±1.41±0.93±0.70±0.65±0.23±0.004±0.004 FIGURE2.Firstorderequationsoptimizedfordifferenttemperatureranges. 2.0Mounting TheLM20canbeappliedeasilyinthesamewayasotherintegrated-circuittemperaturesensors.Itcanbegluedorce-mentedtoasurface.ThetemperaturethattheLM20issens-ingwillbewithinabout+0.02˚CofthesurfacetemperaturetowhichtheLM20’sleadsareattachedto. Thispresumesthattheambientairtemperatureisalmostthesameasthesurfacetemperature;iftheairtemperatureweremuchhigherorlowerthanthesurfacetemperature,theac-tualtemperaturemeasuredwouldbeatanintermediatetem-peraturebetweenthesurfacetemperatureandtheairtem-perature. ToensuregoodthermalconductivitythebacksideoftheLM20dieisdirectlyattachedtothepin2GNDpin.Thetem-perturesofthelandsandtracestotheotherleadsoftheLM20willalsoaffectthetemperaturethatisbeingsensed.Alternatively,theLM20canbemountedinsideasealed-endmetaltube,andcanthenbedippedintoabathorscrewedintoathreadedholeinatank.AswithanyIC,theLM20andaccompanyingwiringandcircuitsmustbekeptinsulatedanddry,toavoidleakageandcorrosion.Thisisespeciallytrueifthecircuitmayoperateatcoldtemperatureswhereconden-sationcanoccur.Printed-circuitcoatingsandvarnishessuch asHumisealandepoxypaintsordipsareoftenusedtoen-surethatmoisturecannotcorrodetheLM20oritsconnec-tions. Thethermalresistancejunctiontoambient(θJA)isthepa-rameterusedtocalculatetheriseofadevicejunctiontem-peratureduetoitspowerdissipation.FortheLM20theequationusedtocalculatetheriseinthedietemperatureisasfollows: TJ=TA+θJA[(V+IQ)+(V+−VO)IL]whereIQisthequiescentcurrentandIListheloadcurrentontheoutput.SincetheLM20’sjunctiontemperatureistheac-tualtemperaturebeingmeasuredcareshouldbetakentominimizetheloadcurrentthattheLM20isrequiredtodrive.ThetablesshowninFigure3summarizetheriseindietem-peratureoftheLM20withoutanyloading,andthethermalresistancefordifferentconditions. 5www.national.com 元器件交易网www.cecb2b.com LM202.0Mounting (Continued) 3.0CapacitiveLoads SC70-5smallheatsinkθJA(˚C/W)350266 TJ−TA(˚C)0.190.15 TheLM20handlescapacitiveloadingwell.Withoutanypre-cautions,theLM20candriveanycapacitiveloadlessthan300pFasshowninFigure4.OverthespecifiedtemperaturerangetheLM20hasamaximumoutputimpedanceof160Ω.Inanextremelynoisyenvironmentitmaybenecessarytoaddsomefilteringtominimizenoisepickup.Itisrecom-mendedthat0.1µFbeaddedfromV+toGNDtobypassthepowersupplyvoltage,asshowninFigure5.Inanoisyenvi-ronmentitmayevenbenecessarytoaddacapacitorfromtheoutputtogroundwithaseriesresistorasshowninFigure5.A1µFoutputcapacitorwiththe160Ωmaximumoutputimpedanceanda200Ωseriesresistorwillforma442Hzlowpassfilter.SincethethermaltimeconstantoftheLM20ismuchslower,theoverallresponsetimeoftheLM20willnotbesignificantlyaffected. SC70-5noheatsinkθJA(˚C/W) StillairMovingair 412312 TJ−TA(˚C)0.20.17 SeeFigure1forPCBlayoutsamples. microSMDnoheatsinkθJA(˚C/W) StillairMovingair TBDTBD TJ−TA(˚C)TBDTBD microSMDsmallheatfinθJA(˚C/W)TBDTBD TJ−TA(˚C)TBDTBD DS100908-15 FIGURE3.TemperatureRiseofLM20DuetoSelf-HeatingandThermalResistance(θJA) FIGURE4.LM20NoDecouplingRequiredfor CapacitiveLoadsLessthan300pF. R(Ω)2004706801k C(µF)10.10.010.001 DS100908-16 DS100908-33 FIGURE5.LM20withFilterforNoisyEnvironmentandCapacitiveLoadinggreaterthan300pF.Eitherplacementof resistorasshownaboveisjustaseffective. 4.0LM20microSMDLightSensitivity ExposingtheLM20microSMDpackagetobrightsunlightmaycausetheoutputreadingoftheLM20todropby1.5V.Inanormalofficeenvironmentoffluorescentlightingtheoutputvoltageisminimallyaffected(lessthanamillivoltdrop).Inei-thercaseitisrecommendedthattheLM20microSMDbe placedinsideanenclosureofsometypethatminimizesitslightexposure.Mostchassisprovidemorethanamplepro-tection.TheLM20doesnotsustainpermanentdamagefromlightexposure.RemovingthelightsourcewillcauseLM20’soutputvoltagetorecovertothepropervalue. www.national.com6 元器件交易网www.cecb2b.com LM205.0ApplicationsCircuits DS100908-18 FIGURE6.CentigradeThermostat DS100908-19 FIGURE7.ConservingPowerDissipationwithShutdown DS100908-28 MostCMOSADCsfoundinASICshaveasampleddatacomparatorinputstructurethatisnotoriousforcausinggrieftoanalogoutputdevicessuchastheLM20andmanyopamps.ThecauseofthisgriefistherequirementofinstantaneouschargeoftheinputsamplingcapacitorintheADC.Thisrequirementiseasilyaccommodatedbytheadditionofacapacitor.SincenotallADCshaveidenticalinputstages,thechargerequirementswillvarynecessitatingadifferentvalueofcompensatingcapacitor.ThisADCisshownasanexampleonly.IfadigitaloutputtemperatureisrequiredpleaserefertodevicessuchastheLM74. FIGURE8.SuggestedConnectiontoaSamplingAnalogtoDigitalConverterInputStage 7www.national.com 元器件交易网www.cecb2b.com LM20PhysicalDimensions inches(millimeters)unlessotherwisenoted 5-LeadSC70MoldedPackage OrderNumberLM20BIM7orLM20CIM7X NSPackageNumberMAA05A www.national.com8 元器件交易网www.cecb2b.com LM202.4V,10µA,SC70,microSMDTemperatureSensorPhysicalDimensions inches(millimeters)unlessotherwisenoted(Continued) 4-BumpmicroSMDBallGridArrayPackageOrderNumberLM20SIBPorLM20SIBPX NSPackageNumberBPA04DDC ThefollowingdimensionsapplytotheBPA04DDCpackageshownabove:X1=X2=853µm±30µm,X3=900µm±50µm LIFESUPPORTPOLICY NATIONAL’SPRODUCTSARENOTAUTHORIZEDFORUSEASCRITICALCOMPONENTSINLIFESUPPORTDEVICESORSYSTEMSWITHOUTTHEEXPRESSWRITTENAPPROVALOFTHEPRESIDENTANDGENERALCOUNSELOFNATIONALSEMICONDUCTORCORPORATION.Asusedherein:1.Lifesupportdevicesorsystemsaredevicesorsystemswhich,(a)areintendedforsurgicalimplantintothebody,or(b)supportorsustainlife,andwhosefailuretoperformwhenproperlyusedinaccordancewithinstructionsforuseprovidedinthelabeling,canbereasonablyexpectedtoresultinasignificantinjurytotheuser. NationalSemiconductorCorporationAmericas Tel:1-800-272-9959Fax:1-800-737-7018Email:support@nsc.com www.national.com NationalSemiconductorEurope Fax:+49(0)180-5308586Email:europe.support@nsc.com DeutschTel:+49(0)180-5308585EnglishTel:+49(0)180-5327832FrançaisTel:+49(0)180-5329358ItalianoTel:+49(0)180-5341680 2.Acriticalcomponentisanycomponentofalifesupportdeviceorsystemwhosefailuretoperformcanbereasonablyexpectedtocausethefailureofthelifesupportdeviceorsystem,ortoaffectitssafetyoreffectiveness. NationalSemiconductorAsiaPacificCustomerResponseGroupTel:65-2544466Fax:65-2504466 Email:sea.support@nsc.com NationalSemiconductorJapanLtd. Tel:81-3-5639-7560Fax:81-3-5639-7507 Nationaldoesnotassumeanyresponsibilityforuseofanycircuitrydescribed,nocircuitpatentlicensesareimpliedandNationalreservestherightatanytimewithoutnoticetochangesaidcircuitryandspecifications. 因篇幅问题不能全部显示，请点此查看更多更全内容