LM71
SPI/MICROWIRE™13-BitPlusSignTemperatureSensor
GeneralDescription
TheLM71isalow-power,high-resolutiondigitaltemperaturesensorwithanSPIandMICROWIREcompatibleinterface,availableinthe5-pinSOT23orthe6-pinLLP(nopullback)package.ThehostcanquerytheLM71atanytimetoreadtemperature.Itslowoperatingcurrentisusefulinsystemswherelowpowerconsumptioniscritical.
TheLM71has13-bitplussigntemperatureresolution(0.03125˚CperLSB)whileoperatingoveratemperaturerangeof−40˚Cto+150˚C.
TheLM71’s2.65Vto5.5Vsupplyvoltagerange,fastcon-versionrate,lowsupplycurrent,andsimpleSPIinterfacemakeitidealforawiderangeofapplications.
nElectronicTestEquipmentnVendingMachines
Features
nSOT23-5orNo-Pull-BackLLP-6PackagesnOperatesoverafull−40˚Cto+150˚CrangenSPIandMICROWIREBusinterface
KeySpecifications
jSupplyVoltagejSupplyCurrentjTemperature
2.65Vto5.5V
operating
300µA(typ)550µA(max)
Applications
nnnnn
SystemThermalManagementPersonalComputers
PortableElectronicDevicesDiskDrives
OfficeElectronics
Accuracy
jTemperature
−10˚Cto+65˚C−40˚Cto150˚C
±1.5˚C(max)
+3/−2˚C(max)
31.25m˚C
Resolution
SimplifiedBlockDiagram
20031701
MICROWIRE™isatrademarkofNationalSemiconductorCorporation.
TRI-STATE®isaregisteredtrademarkofNationalSemiconductorCorporation.
©2004NationalSemiconductorCorporationDS200317www.national.com
LM71ConnectionDiagrams
SOT23-5
LLP-6NoPull-Back
20031728
20031702
TOPVIEW
NSPackageNumberMF05A
TOPVIEW
NSPackageNumberSDE06A
OrderingInformation
OrderNumberLM71CIMFLM71CISD
PackageMarkingT16CLM71C
NSPackageNumberMF05ASDE06A
SupplyVoltage2.65Vto5.5V2.65Vto5.5V
TransportMedia3000UnitsinTapeandReel4500UnitsinTapeandReel
www.national.com2
LM71PinDescriptions
LabelCSGNDSI/OSCV+PinNumberSOT23-5
12345
LLP-642,5316
ChipSelectinputPowerSupplyGround
SlaveInput/Output-Serialbus
bi-directionaldataline.Shmitttriggerinput.SlaveClock-SerialbusclockShmitttriggerinputline
PositiveSupplyVoltageInput
Fromcontroller
ConnectallGNDPinstogroundFromandtocontrollerFromcontroller
DCvoltagefrom2.65Vto5.5V.Bypasswitha0.1µFceramiccapacitor.
Function
TypicalConnection
TypicalApplication
20031703
FIGURE1.COPMicrocontrollerInterface
3www.national.com
LM71AbsoluteMaximumRatings(Note1)
SupplyVoltageVoltageatanyPin
InputCurrentatanyPin(Note2)StorageTemperatureSOT23-5Package(Note3)VaporPhase(60seconds)Infrared(15seconds)LLP-6Package(Note3)Infrared(5seconds)
SolderingInformation,LeadTemperature
215˚C220˚C215˚C
−0.3Vto6.0V−0.3VtoV++0.3V
5mA
−65˚Cto+150˚C
ESDSusceptibility(Note4)HumanBodyModelMachineModel
2000V200V
OperatingRatings
SpecifiedTemperatureRange(Note5)LM71CIMF,LM71CISDSupplyVoltageRange(+VS)LM71CIMF,LM71CISD
+2.65Vto+5.5VTMINtoTMAX−40˚Cto+150˚C
Unlessotherwisenoted,thesespecifica-tionsapplyforV=2.65Vto3.6V(Note6).BoldfacelimitsapplyforTA=TJ=TMINtoTMAX;allotherlimitsTA=TJ=+25˚C,unlessotherwisenoted.
+Temperature-to-DigitalConverterCharacteristics
ParameterConditions
Typical(Note7)
LM71CIMFLM71CISDLimits(Note8)
Units(Limit)˚C(max)˚C(max)˚C(max)Bits˚C
TemperatureError(Note6)
TA=−10˚Cto+65˚CTA=−40˚Cto+85˚CTA=−40˚Cto+150˚C
±1.5±2.0
+3/−2
140.03125
ResolutionTemperatureConversionTimeQuiescentCurrent
(Note9)
SerialBusInactive
200300
270550
ms(max)µA(max)
LogicElectricalCharacteristics
DIGITALDCCHARACTERISTICSUnlessotherwisenoted,thesespecificationsapplyforV+=2.65Vto3.6V(Note6).Bold-facelimitsapplyforTA=TJ=TMINtoTMAX;allotherlimitsTA=TJ=+25˚C,unlessotherwisenoted.SymbolVIN(1)VIN(0)Parameter
Logical“1”InputVoltageLogical“0”InputVoltageInputHysteresisVoltage
IIN(1)IIN(0)CINVOHVOLIO_TRI-STATELogical“1”InputCurrentLogical“0”InputCurrentAllDigitalInputs
HighLevelOutputVoltageLowLevelOutputVoltageTRI-STATE®OutputLeakageCurrent
IOH=−400µAIOL=+2mAVO=GNDVO=V+V=3.0Vto3.6VVIN=V
++Conditions
Typical(Note7)Limits(Note8)V+x0.7V++0.3−0.3V+x0.3
Units(Limit)V(min)V(max)V(min)V(max)V(min)µA(max)µA(min)pFV(min)V(max)µA(min)µA(max)
0.40.005−0.00520
0.333.0−3.02.40.4−1+1
VIN=0V
www.national.com4
LM71LogicElectricalCharacteristics
(Continued)
SERIALBUSDIGITALSWITCHINGCHARACTERISTICSUnlessotherwisenoted,thesespecificationsapplyforV+=2.65Vto3.6V(Note6);CL(loadcapacitance)onoutputlines=100pFunlessotherwisespecified.BoldfacelimitsapplyforTA=TJ=TMINtoTMAX;allotherlimitsTA=TJ=+25˚C,unlessotherwisenoted.Symbolt1t2t3t4t5t6t7SC(Clock)Period
CSLowtoSC(Clock)HighSet-UpTimeCSLowtoDataOut(SO)DelaySC(Clock)LowtoDataOut(SO)DelayCSHightoDataOut(SO)TRI-STATESC(Clock)HightoDataIn(SI)HoldTimeDataIn(SI)Set-UpTimetoSC(Clock)High
Parameter
Conditions
Typical(Note7)
Limits(Note8)0.16DC10070702005030
Units(Limit)µs(min)(max)ns(min)ns(max)ns(max)ns(max)ns(min)ns(min)
20031704
FIGURE2.DataOutputTimingDiagram
20031705
FIGURE3.TRI-STATEDataOutputTimingDiagram
5www.national.com
LM71LogicElectricalCharacteristics
(Continued)
20031706
FIGURE4.DataInputTimingDiagram
Note1:AbsoluteMaximumRatingsindicatelimitsbeyondwhichdamagetothedevicemayoccur.DCandACelectricalspecificationsdonotapplywhenoperatingthedevicebeyonditsratedoperatingconditions.
Note2:Whentheinputvoltage(VI)atanypinexceedsthepowersupplies(VI Note3:SeeAN-450“SurfaceMountingMethodsandTheirEffectonProductReliability”orthesectiontitled“SurfaceMount”foundinacurrentNationalSemiconductorLinearDataBookforothermethodsofsolderingsurfacemountdevices. Note4:Humanbodymodel,100pFdischargedthrougha1.5kΩresistor.Machinemodel,200pFdischargeddirectlyintoeachpin. Note5:ThelifeexpectancyoftheLM71willbereducedwhenoperatingatelevatedtemperatures.LM71θJA(thermalresistance,junction-to-ambient)whenattachedtoaprintedcircuitboardwith2oz.foilissummarizedinthetablebelow: DeviceNumberLM71CIMFLM71CISD NSPackageNumberMF05ASDE06A ThermalResistance(θJA) 250˚C/W57.6˚C/W Note6:TheLM71willoperateproperlyovertheV+supplyvoltagerangeof2.65Vto5.5V.Note7:TypicalsareatTA=25˚Candrepresentmostlikelyparametricnorm. Note8:LimitsareguaranteedtoNational’sAOQL(AverageOutgoingQualityLevel). Note9:Thisspecificationisprovidedonlytoindicatehowoftentemperaturedataisupdated.TheLM71canbereadatanytimewithoutregardtoconversionstate(andwillyieldlastconversionresult).Aconversioninprogresswillnotbeinterrupted.Theoutputshiftregisterwillbeupdatedatthecompletionofthereadandanewconversionrestarted. Note10:Forbestaccuracy,minimizeoutputloading.Highersinkcurrentscanaffectsensoraccuracywithinternalheating.Thiscancauseanerrorof0.64˚Catfullratedsinkcurrentandsaturationvoltagebasedonjunction-to-ambientthermalresistance. www.national.com6 LM71ElectricalCharacteristics 20031708 FIGURE5.Temperature-to-DigitalTransferFunction(Non-linearscaleforclarity) TRI-STATETestCircuit 20031707 FIGURE6. 7www.national.com LM71TypicalPerformanceCharacteristics StaticSupplyCurrentvs.Temperature TemperatureError 2003179620031797 1.0FunctionalDescription TheLM71temperaturesensorincorporatesatemperaturesensorand13-bitplussign∆ΣADC(Delta-SigmaAnalog-to-DigitalConverter).CompatibilityoftheLM71’sthreewireserialinterfacewithSPIandMICROWIREallowssimplecommunicationswithcommonmicrocontrollersandproces-sors.Shutdownmodecanbeusedtooptimizecurrentdrainfordifferentapplications.AManufacture’s/DeviceIDregisteridentifiestheLM71asNationalSemiconductorproduct.1.1POWERUPANDPOWERDOWN TheLM71alwayspowersupinaknownstate.Thepowerupdefaultconditioniscontinuousconversionmode.Immedi-atelyafterpoweruptheLM71willoutputanerroneouscodeuntilthefirsttemperatureconversionhascompleted. Whenthesupplyvoltageislessthanabout1.6V(typical),theLM71isconsideredpowereddown.Asthesupplyvolt-agerisesabovethenominal1.6Vpowerupthreshold,theinternalregistersareresettothepowerupdefaultstatedescribedabove. 1.2SERIALBUSINTERFACE TheLM71operatesasaslaveandiscompatiblewithSPIorMICROWIREbusspecifications.Dataisclockedoutonthefallingedgeoftheserialclock(SC),whiledataisclockedinontherisingedgeofSC.Acompletetransmit/receivecom-municationwillconsistof32serialclocks.Thefirst16clockscomprisethetransmitphaseofcommunication,whilethesecond16clocksarethereceivephase. WhenCSishighSI/OwillbeinTRI-STATE.Communicationshouldbeinitiatedbytakingchipselect(CS)low.ThisshouldnotbedonewhenSCischangingfromalowtohighstate.OnceCSislowtheserialI/Opin(SI/O)willtransmitthefirstbitofdata.ThemastercanthenreadthisbitwiththerisingedgeofSC.TheremainderofthedatawillbeclockedoutbythefallingedgeofSC.CScanbetakenhighatany timeduringthetransmitphase.IfCSisbroughtlowinthemiddleofaconversiontheLM71willcompletetheconver-sionandtheoutputshiftregisterwillbeupdatedafterCSisbroughtbackhigh. Thereceivephaseofacommunicationstartsafter16SCperiods.CScanremainlowfor32SCcycles.TheLM71willreadthedataavailableontheSI/Olineontherisingedgeoftheserialclock.Inputdataistoan8-bitshiftregister.Thepartwilldetectthelasteightbitsshiftedintotheregister.Thereceivephasecanlastupto16SCperiods.Allonesmustbeshiftedinordertoplacethepartintoshutdown.AllzerosmustbeshiftedinordertoplacetheLM71intocontinuousconversionmode.Onlythefollowingcodesshouldbetrans-mittedtotheLM71: •00hexforcontinuousconversion•FFhexforshutdown Anothercodemayplacethepartintoatestmode.TestmodesareusedbyNationalSemiconductortothoroughlytestthefunctionoftheLM71duringproductiontesting.OnlyeightbitshavebeendefinedabovesinceonlythelasteighttransmittedaredetectedbytheLM71,beforeCSistakenHIGH. ThefollowingcommunicationcanbeusedtodeterminetheManufacturer’s/DeviceIDandthenimmediatelyplacethepartintocontinuousconversionmode.WithCScontinuouslylow: •Read16bitsoftemperaturedata •Write16bitsofdatacommandingshutdown•Read16bitsofManufacture’s/DeviceIDdata •Write8to16bitsofdatacommandingConversionMode•TakeCSHIGH. Notethat300mswillhavetopassforaconversiontocompletebeforetheLM71actuallytransmitstemperaturedata. www.national.com8 LM711.0FunctionalDescription 1.3TEMPERATUREDATAFORMAT (Continued) Temperaturedataisrepresentedbya14-bit,two’scomple-mentwordwithanLSB(LeastSignificantBit)equalto0.03125˚C:Temperature+150˚C+125˚C+25˚C+0.03125˚C 0˚C−0.03125˚C−25˚C−40˚C DigitalOutputBinary 01001011000000110011111010000011000011001000001100000000000001110000000000000011111111111111111111110011100000111110110000000011 Hex4B033E830C8300070003FFFFF383EC03 sarytobereadtodeterminetemperaturecondition.Forinstance,ifthefirstfourbitsofthetemperaturedataindicateanovertemperaturecondition,thehostprocessorcouldim-mediatelytakeactiontoremedytheexcessivetempera-tures. 1.4SHUTDOWNMODE/MANUFACTURER’SID ShutdownmodeisenabledbywritingXXFFtotheLM71asshowninFigure7c.TheserialbusisstillactivewhentheLM71isinshutdown.WheninshutdownmodetheLM71alwayswilloutput1000000000001111.Thisisthemanufacturer’s/DeviceIDinformation.Thefirst5-bitsofthefield(10000XXX)arereservedformanufacturer’sID.1.5INTERNALREGISTERSTRUCTURE TheLM71hasthreeregisters,thetemperatureregister,theconfigurationregisterandthemanufacturer’s/deviceidentifi-cationregister.Thetemperatureandmanufacturer’s/deviceidentificationregistersarereadonly.Theconfigurationreg-isteriswriteonly. Thefirstdatabyteisthemostsignificantbytewithmostsignificantbitfirst,permittingonlyasmuchdataasneces-1.5.1ConfigurationRegister (Selectsshutdownorcontinuousconversionmodes):(WriteOnly):D15X D14X D13X D12X D11X D10X D9X D8X D7 D6 D5 D4 D3 D2 D1 D0 Shutdown D0–D15settoXXFFhexenablesshutdownmode. D0–D15setto0000hexsetsContinuousconversionmode. Note:settingD0-D15toanyothervaluesmayplacetheLM70intoamanufacturer’stestmode,uponwhichtheLM71willstoprespondingasdescribed.ThesetestmodesaretobeusedforNationalSemiconductorproductiontestingonly.SeeSection1.2SerialBusInterfaceforacompletediscussion.1.5.2TemperatureRegister(ReadOnly):D15MSB D14 D13 D12 D11Bit9 D10Bit8 D9Bit7 D8Bit6 D7Bit5 D6Bit4 D5Bit3 D4Bit2 D3Bit1 D2LSB D11 D01 Bit12Bit11Bit10 D0–D1:Logic1willbeoutputonSI/0. D2–D15:TemperatureData.OneLSB=0.03125˚C.Two’scomplementformat.1.5.3Manufacturer/DeviceIDRegister(ReadOnly):D151 D140 D130 D120 D110 D100 D90 D80 D70 D60 D50 D40 D31 D21 D11 D01 D0–D1:Logic1willbeoutputonSI/0. D2–D15:Manufacturer’s/DeviceIDData.ThisregisterisaccessedwhenevertheLM71isinshutdownmode. 9www.national.com LM712.0SerialBusTimingDiagrams 20031714 a)ReadingContinuousConversion-SingleEight-BitFrame 20031715 b)ReadingContinuousConversion-TwoEight-BitFrames 20031718 c)WritingShutdownControlFIGURE7.TimingDiagrams 3.0ApplicationHints TogettheexpectedresultswhenmeasuringtemperaturewithanintegratedcircuittemperaturesensorliketheLM71,itisimportanttounderstandthatthesensormeasuresitsowndietemperature.FortheLM71,thebestthermalpathbetweenthedieandtheoutsideworldisthroughtheLM71’spins.IntheSOT23package,allthepinsontheLM71willhaveanequaleffectonthedietemperature.BecausethepinsrepresentagoodthermalpathtotheLM71die,theLM71willprovideanaccuratemeasurementofthetempera-tureoftheprintedcircuitboardonwhichitismounted.ThereisalessefficientthermalpathbetweentheplasticpackageandtheLM71die.Iftheambientairtemperatureissignifi- cantlydifferentfromtheprintedcircuitboardtemperature,itwillhaveasmalleffectonthemeasuredtemperature. Inprobe-typeapplications,theLM71canbemountedinsideasealed-endmetaltube,andcanthenbedippedintoabathorscrewedintoathreadedholeinatank.AswithanyIC,theLM71andaccompanyingwiringandcircuitsmustbekeptinsulatedanddry,toavoidleakageandcorrosion.Thisisespeciallytrueifthecircuitmayoperateatcoldtemperatureswherecondensationcanoccur.Printed-circuitcoatingsandvarnishessuchasHumisealandepoxypaintsordipsareoftenusedtoinsurethatmoisturecannotcorrodetheLM71oritsconnections. www.national.com10 LM714.0TypicalApplications 20031720 FIGURE8.TemperaturemonitorusingIntel196processor 20031719 FIGURE9.LM71digitalinputcontrolusingmicro-controller’sgeneralpurposeI/O. 11www.national.com LM71PhysicalDimensions inches(millimeters)unlessotherwisenoted OrderNumberLM71TopView CIMF NSPackageNumberMF05A www.national.com12 LM71SPI/MICROWIRE13-BitPlusSignTemperatureSensorPhysicalDimensions inches(millimeters)unlessotherwisenoted(Continued) OrderNumberLM71BottomView CISD NSPackageNumberSDE06A LIFESUPPORTPOLICY NATIONAL’SPRODUCTSARENOTAUTHORIZEDFORUSEASCRITICALCOMPONENTSINLIFESUPPORTDEVICESORSYSTEMSWITHOUTTHEEXPRESSWRITTENAPPROVALOFTHEPRESIDENTANDGENERALCOUNSELOFNATIONALSEMICONDUCTORCORPORATION.Asusedherein:1.Lifesupportdevicesorsystemsaredevicesorsystemswhich,(a)areintendedforsurgicalimplantintothebody,or(b)supportorsustainlife,andwhosefailuretoperformwhenproperlyusedinaccordancewithinstructionsforuseprovidedinthelabeling,canbereasonablyexpectedtoresultinasignificantinjurytotheuser.BANNEDSUBSTANCECOMPLIANCE NationalSemiconductorcertifiesthattheproductsandpackingmaterialsmeettheprovisionsoftheCustomerProductsStewardshipSpecification(CSP-9-111C2)andtheBannedSubstancesandMaterialsofInterestSpecification(CSP-9-111S2)andcontainno‘‘BannedSubstances’’asdefinedinCSP-9-111S2. NationalSemiconductorAmericasCustomerSupportCenter Email:new.feedback@nsc.comTel:1-800-272-9959 www.national.com NationalSemiconductor EuropeCustomerSupportCenter Fax:+49(0)180-5308586Email:europe.support@nsc.com DeutschTel:+49(0)6995086208EnglishTel:+44(0)8702402171FrançaisTel:+33(0)141918790 NationalSemiconductorAsiaPacificCustomerSupportCenter Email:ap.support@nsc.com NationalSemiconductor JapanCustomerSupportCenterFax:81-3-5639-7507 Email:jpn.feedback@nsc.comTel:81-3-5639-7560 2.Acriticalcomponentisanycomponentofalifesupportdeviceorsystemwhosefailuretoperformcanbereasonablyexpectedtocausethefailureofthelifesupportdeviceorsystem,ortoaffectitssafetyoreffectiveness. Nationaldoesnotassumeanyresponsibilityforuseofanycircuitrydescribed,nocircuitpatentlicensesareimpliedandNationalreservestherightatanytimewithoutnoticetochangesaidcircuitryandspecifications. 因篇幅问题不能全部显示，请点此查看更多更全内容