LM334恒流芯片

LM134/LM234/LM3343-TerminalAdjustableCurrentSources

March2000

LM134/LM234/LM334

3-TerminalAdjustableCurrentSources

GeneralDescription

The

LM134/LM234/LM334are3-terminaladjustablecurrentsourcesfeaturing10,000:1rangeinoperatingcurrent,excel-lentcurrentregulationandawidedynamicvoltagerangeof1Vto40V.Currentisestablishedwithoneexternalresistorandnootherpartsarerequired.Initialcurrentaccuracyis±3%.TheLM134/LM234/LM334aretruefloatingcurrentsourceswithnoseparatepowersupplyconnections.Inaddi-tion,reverseappliedvoltagesofupto20Vwilldrawonlyafewdozenmicroamperesofcurrent,allowingthedevicestoactasbotharectifierandcurrentsourceinACapplications.ThesensevoltageusedtoestablishoperatingcurrentintheLM134is64mVat25˚Candisdirectlyproportionaltoabso-lutetemperature(˚K).Thesimplestoneexternalresistorconnection,then,generatesacurrentwith≈+0.33%/˚Ctem-peraturedependence.Zerodriftoperationcanbeobtainedbyaddingoneextraresistorandadiode.

Applicationsforthecurrentsourcesincludebiasnetworks,surgeprotection,lowpowerreference,rampgeneration,

LEDdriver,andtemperaturesensing.TheLM234-3andLM234-6arespecifiedastruetemperaturesensorswithguaranteedinitialaccuracyof±3˚Cand±6˚C,respectively.Thesedevicesareidealinremotesenseapplicationsbe-causeseriesresistanceinlongwirerunsdoesnotaffectac-curacy.Inaddition,only2wiresarerequired.

TheLM134isguaranteedoveratemperaturerangeof−55˚Cto+125˚C,theLM234from−25˚Cto+100˚CandtheLM334from0˚Cto+70˚C.ThesedevicesareavailableinTO-46hermetic,TO-92andSO-8plasticpackages.

Features

nnnnnn

Operatesfrom1Vto40V0.02%/Vcurrentregulation

Programmablefrom1µAto10mATrue2-terminaloperation

Availableasfullyspecifiedtemperaturesensor±3%initialaccuracy

ConnectionDiagrams

SO-8

SurfaceMountPackage

SO-8AlternativePinoutSurfaceMountPackage

TO-46

MetalCanPackage

DS005697-24

DS005697-12

DS005697-25

OrderNumberLM334Mor

LM334MX

SeeNSPackageNumberM08A

OrderNumberLM334SMor

LM334SMX

SeeNSPackageNumberM08A

VPiniselectricallyconnectedtocase.

−

BottomView

OrderNumberLM134H,LM234HorLM334HSeeNSPackageNumberH03H

TO-92PlasticPackage

DS005697-10

BottomView

OrderNumberLM334Z,LM234Z-3orLM234Z-6

SeeNSPackageNumberZ03A

2000NationalSemiconductorCorporationDS005697www.national.com

LM134/LM234/LM334

AbsoluteMaximumRatings

(Note1)

IfMilitary/Aerospacespecifieddevicesarerequired,pleasecontacttheNationalSemiconductorSalesOffice/Distributorsforavailabilityandspecifications.V+toV−ForwardVoltageLM134/LM234/LM334LM234-3/LM234-6+

VtoV−ReverseVoltageRPintoV−VoltageSetCurrent

PowerDissipation

ESDSusceptibility(Note6)

OperatingTemperatureRange(Note5)LM134

40V30V20V5V10mA400mW2000V

−55˚Cto+125˚C

LM234/LM234-3/LM234-6−25˚Cto+100˚CLM3340˚Cto+70˚CSolderingInformation

TO-92Package(10sec.)260˚CTO-46Package(10sec.)300˚CSOPackage

VaporPhase(60sec.)215˚CInfrared(15sec.)220˚CSeeAN-450“SurfaceMountingMethodsandTheirEffectonProductReliability”(AppendixD)forothermethodsofsol-deringsurfacemountdevices.

ElectricalCharacteristics(Note2)

Parameter

SetCurrentError,V+=2.5V,(Note3)

RatioofSetCurrenttoBiasCurrent

MinimumOperatingVoltage

Conditions

Min

10µA≤ISET≤1mA1mA

1mA

AverageChangeinSetCurrentwithInputVoltage

2µA≤ISET≤1mA1.5≤V+≤5V5V≤V≤40V1mA

TemperatureDependenceofSetCurrent(Note4)EffectiveShuntCapacitance

Note1:.“AbsoluteMaximumRatings”indicatelimitsbeyondwhichdamagetothedevicemayoccur.OperatingRatingsindicateconditionsforwhichthedeviceisfunctional,butdonotguaranteespecificperformancelimits.

Note2:Unlessotherwisespecified,testsareperformedatTj=25˚Cwithpulsetestingsothatjunctiontemperaturedoesnotchangeduringtest

Note3:SetcurrentisthecurrentflowingintotheV+pin.FortheBasic2-TerminalCurrentSourcecircuitshownonthefirstpageofthisdatasheet.ISETisdeterminedbythefollowingformula:ISET=67.7mV/RSET(@25˚C).Setcurrenterrorisexpressedasapercentdeviationfromthisamount.ISETincreasesat0.336%/˚C@Tj=25˚C(227µV/˚C).

Note4:ISETisdirectlyproportionaltoabsolutetemperature(˚K).ISETatanytemperaturecanbecalculatedfrom:ISET=Io(T/To)whereIoisISETmeasuredatTo(˚K).

Note5:Forelevatedtemperatureoperation,TJmaxis:

LM134/LM234

Typ

Max358

1814180.80.91.00.020.010.030.02

0.96T

1.04T

0.96T

0.050.032323

14Min

LM334Typ

Max6812

1814180.80.91.00.020.010.030.02T

1.04T0.10.052626

Units%%%

VVV%/V%/V%/V%/V

25µA≤ISET≤1mA

LM134LM234LM334

ThermalResistanceθja(JunctiontoAmbient)θjc(JunctiontoCase)

150˚C125˚C100˚C

TO-92

180˚C/W(0.4"leads)160˚C/W(0.125"leads)

N/A

32˚C/W

80˚C/W

TO-46440˚C/W

SO-8165˚C/W

Note6:Humanbodymodel,100pFdischargedthrougha1.5kΩresistor.

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LM134/LM234/LM334

ElectricalCharacteristics(Note

Parameter

SetCurrentError,V+=2.5V,(Note3)

EquivalentTemperatureErrorRatioofSetCurrenttoBiasCurrent

MinimumOperatingVoltageAverageChangeinSetCurrentwithInputVoltage

TemperatureDependenceofSetCurrent(Note4)andEquivalentSlopeErrorEffectiveShuntCapacitance

100µAISET≤1mA100µA≤ISET≤1mA

1.5≤V+≤5V5V≤V+≤30V100µA≤ISET≤1mA

0.98T

0.020.01T

0.050.031.02T

0.97T

0.020.01T

0.010.051.03T

%/V%/V

0.9

100µA≤ISET≤1mA

Conditions

Min

100µA≤ISET≤1mATJ=25˚

LM234-3Typ

Max

Min

LM234-6Typ

Max

Units

±1±2

±3

±6

˚C

±2

±3

%pF

3www.national.com

LM134/LM234/LM334

TypicalPerformanceCharacteristics

OutputImpedance

MaximumSlewRateLinearOperation

DS005697-30

DS005697-31

Start-UpTransientResponse

DS005697-32

DS005697-33

VoltageAcrossRSET(VR)CurrentNoise

DS005697-34

DS005697-35

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LM134/LM234/LM334

TypicalPerformanceCharacteristics

Turn-OnVoltage

(Continued)

RatioofISETtoIBIAS

DS005697-29

DS005697-3

ApplicationHints

TheLM134hasbeendesignedforeaseofapplication,butageneraldiscussionofdesignfeaturesispresentedheretofamiliarizethedesignerwithdevicecharacteristicswhichmaynotbeimmediatelyobvious.Theseincludetheeffectsofslewing,powerdissipation,capacitance,noise,andcon-tactresistance.CALCULATINGRSET

ThetotalcurrentthroughtheLM134(ISET)isthesumofthecurrentgoingthroughtheSETresistor(IR)andtheLM134’sbiascurrent(IBIAS),asshowninFigure1.

wherenistheratioofISETtoIBIASasspecifiedintheElec-tricalCharacteristicsSectionandshowninthegraph.Sincenistypically18for2µA≤ISET≤1mA,theequationcanbefurthersimplifiedto

formostsetcurrents.

SLEWRATE

Atslewratesaboveagiventhreshold(seecurve),theLM134mayexhibitnon-linearcurrentshifts.TheslewingrateatwhichthisoccursisdirectlyproportionaltoISET.AtISET=10µA,maximumdV/dtis0.01V/µs;atISET=1mA,thelimitis1V/µs.SlewratesabovethelimitdonotharmtheLM134,orcauselargecurrentstoflow.

THERMALEFFECTS

Internalheatingcanhaveasignificanteffectoncurrentregu-lationforISETgreaterthan100µA.Forexample,each1Vin-creaseacrosstheLM134atISET=1mAwillincreasejunc-tiontemperatureby≈0.4˚Cinstillair.Outputcurrent(ISET)hasatemperaturecoefficientof≈0.33%/˚C,sothechangeincurrentduetotemperaturerisewillbe(0.4)(0.33)=0.132%.Thisisa10:1degradationinregulationcomparedtotrueelectricaleffects.Thermaleffects,therefore,mustbetakenintoaccountwhenDCregulationiscriticalandISETexceeds100µA.HeatsinkingoftheTO-46packageortheTO-92leadscanreducethiseffectbymorethan3:1.

SHUNTCAPACITANCE

Incertainapplications,the15pFshuntcapacitanceoftheLM134mayhavetobereduced,eitherbecauseofloadingproblemsorbecauseitlimitstheACoutputimpedanceofthecurrentsource.ThiscanbeeasilyaccomplishedbybufferingtheLM134withanFETasshownintheapplications.Thiscanreducecapacitancetolessthan3pFandimproveregu-lationbyatleastanorderofmagnitude.DCcharacteristics(withtheexceptionofminimuminputvoltage),arenotaf-fected.

DS005697-27

FIGURE1.BasicCurrentSource

AgraphshowingtheratioofthesetwocurrentsissuppliedunderRatioofISETtoIBIASintheTypicalPerformanceCharacteristicssection.ThecurrentflowingthroughRSETisdeterminedbyVR,whichisapproximately214µV/˚K(64mV/298˚K∼214µV/˚K).

Since(foragivensetcurrent)IBIASissimplyapercentageofISET,theequationcanberewritten

5www.national.com

LM134/LM234/LM334

ApplicationHints

NOISE

(Continued)

APPLICATIONASAZEROTEMPERATURECOEFFICENTCURRENTSOURCE

AddingadiodeandaresistortothestandardLM134con-figurationcancancelthetemperature-dependentcharacter-isticoftheLM134.ThecircuitshowninFigure3balancesthepositivetempcooftheLM134(about+0.23mV/˚C)withthenegativetempcoofaforward-biasedsilicondiode(about−2.5mV/˚C).

CurrentnoisegeneratedbytheLM134isapproximately4timestheshotnoiseofatransistor.IftheLM134isusedasanactiveloadforatransistoramplifier,inputreferrednoisewillbeincreasedbyabout12dB.Inmanycases,thisisac-ceptableandasinglestageamplifiercanbebuiltwithavolt-agegainexceeding2000.LEADRESISTANCE

ThesensevoltagewhichdeterminesoperatingcurrentoftheLM134islessthan100mV.Atthislevel,thermocoupleorleadresistanceeffectsshouldbeminimizedbylocatingthecurrentsettingresistorphysicallyclosetothedevice.Sock-etsshouldbeavoidedifpossible.Ittakesonly0.7Ωcontactresistancetoreduceoutputcurrentby1%atthe1mAlevel.SENSINGTEMPERATURE

TheLM134makesanidealremotetemperaturesensorbe-causeitscurrentmodeoperationdoesnotloseaccuracyoverlongwireruns.OutputcurrentisdirectlyproportionaltoabsolutetemperatureindegreesKelvin,accordingtothefol-lowingformula:

CalibrationoftheLM134isgreatlysimplifiedbecauseofthefactthatmostoftheinitialinaccuracyisduetoagainterm(slopeerror)andnotanoffset.Thismeansthatacalibrationconsistingofagainadjustmentonlywilltrimbothslopeandzeroatthesametime.Inaddition,gainadjustmentisaonepointtrimbecausetheoutputoftheLM134extrapolatestozeroat0˚K,independentofRSEToranyinitialinaccuracy.

DS005697-28

FIGURE3.ZeroTempcoCurrentSource

Thesetcurrent(ISET)isthesumofI1andI2,eachcontribut-ingapproximately50%ofthesetcurrent,andIBIAS.IBIASisusuallyincludedintheI1termbyincreasingtheVRvalueusedforcalculationsby5.9%.(SeeCALCULATINGRSET.)

Thefirststepistominimizethetempcoofthecircuit,usingthefollowingequations.Anexampleisgivenusingavalueof+227µV/˚CasthetempcooftheLM134(whichincludestheIBIAScomponent),and−2.5mV/˚Casthetempcoofthedi-ode(forbestresults,thisvalueshouldbedirectlymeasuredorobtainedfromthemanufacturerofthediode).

DS005697-4

FIGURE2.GainAdjustment

ThispropertyoftheLM134isillustratedintheaccompanyinggraph.Lineabcisthesensorcurrentbeforetrimming.Linea'b'c'isthedesiredoutput.AgaintrimdoneatT2willmovetheoutputfrombtob'andwillsimultaneouslycorrecttheslopesothattheoutputatT1andT3willbecorrect.ThisgaintrimcanbedoneonRSETorontheloadresistorusedtoterminatetheLM134.Slopeerroraftertrimwillnormallybelessthan±1%.Tomaintainthisaccuracy,however,alowtemperaturecoefficientresistormustbeusedforRSET.A33ppm/˚CdriftofRSETwillgivea1%slopeerrorbecausetheresistorwillnormallyseeaboutthesametemperaturevariationsastheLM134.SeparatingRSETfromtheLM134requires3wiresandhasleadresistanceproblems,soisnotnormallyrecommended.Metalfilmresistorswithlessthan20ppm/˚Cdriftarereadilyavailable.Wirewoundresistorsmayalsobeusedwherebeststabilityisrequired.

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WiththeR1toR2ratiodetermined,valuesforR1andR2shouldbedeterminedtogivethedesiredsetcurrent.TheformulaforcalculatingthesetcurrentatT=25˚Cisshownbelow,followedbyanexamplethatassumestheforwardvoltagedropacrossthediode(VD)is0.6V,thevoltageacrossR1is67.7mV(64mV+5.9%toaccountforIBIAS),andR2/R1=10(fromthepreviouscalculations).

LM134/LM234/LM334

ApplicationHints

(Continued)

Iftheestimateforthetempcoofthediode’sforwardvoltagedropwasoff,thetempcocancellationisstillreasonablyef-fective.Assumethetempcoofthediodeis2.6mV/˚Cinsteadof2.5mV/˚C(anerrorof4%).Thetempcoofthecircuitisnow:

ThiscircuitwilleliminatemostoftheLM134’stemperaturecoefficient,anditdoesagoodjobeveniftheestimatesofthediode’scharacteristicsarenotaccurate(asthefollowingex-amplewillshow).ForlowesttempcowithaspecificdiodeatthedesiredISET,however,thecircuitshouldbebuiltandtestedovertemperature.IfthemeasuredtempcoofISETispositive,R2shouldbereduced.Iftheresultingtempcoisnegative,R2shouldbeincreased.Therecommendeddiodeforuseinthiscircuitisthe1N457becauseitstempcoiscen-teredat11timesthetempcooftheLM134,allowingR2=10R1.Youcanalsousethiscircuittocreateacurrentsourcewithnon-zerotempcosbysettingthetempcocomponentofthetempcoequationtothedesiredvalueinsteadof0.EXAMPLE:A1mA,Zero-TempcoCurrentSourceFirst,solveforR1andR2:

A1mALM134currentsourcewithnotemperaturecompen-sationwouldhaveasetresistorof68Ωandaresultingtempcoof

Soevenifthediode’stempcovariesasmuchas±4%fromitsestimatedvalue,thecircuitstilleliminates98%oftheLM134’sinherenttempco.

TypicalApplications

GroundReferredFahrenheitThermometer

ThevaluesofR1andR2canbechangedtostandard1%re-sistorvalues(R1=133ΩandR2=1.33kΩ)withlessthana0.75%error.

Iftheforwardvoltagedropofthediodewas0.65Vinsteadoftheestimateof0.6V(anerrorof8%),theactualsetcurrentwillbe

DS005697-15

*SelectR3=VREF/583µA.VREFmaybeanystablepositivevoltage≥2V

TrimR3tocalibrate

anerroroflessthan5%.

7www.national.com

TypicalApplications

(Continued)

LowOutputImpedance

Thermometer

TerminatingRemoteSensorforVoltage

Output

DS005697-6

*OutputimpedanceoftheLM134atthe“R”pinis

approximately

DS005697-14

LM134/LM234/LM334

TypicalApplications

(Continued)

LowInputVoltageReferenceDriver

MicropowerBias

DS005697-17

DS005697-18

RampGenerator

DS005697-19

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LM134/LM234/LM334

TypicalApplications

(Continued)

1.2VRegulatorwith1.8VMinimumInput

1.2VReferenceOperateson10µAand2V

DS005697-20

*SelectratioofR1toR2toobtainzerotemperaturedrift

DS005697-7

*SelectratioofR1toR2forzerotemperaturedrift

ZenerBiasingAlternateTrimmingTechniqueBufferforPhotoconductiveCell

DS005697-51

DS005697-49

DS005697-50

*For±10%adjustment,selectRSET10%high,andmakeR1≈3RSET

FETCascodingforLowCapacitanceand/orUltraHighOutputImpedance

DS005697-21

*SelectQ1orQ2toensureatleast1VacrosstheLM134.Vp(1−ISET/IDSS)≥1.2V.

DS005697-22

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LM134/LM234/LM334

TypicalApplications

(Continued)

In-LineCurrentLimiter

GeneratingNegativeOutputImpedance

DS005697-23

*ZOUT≈−16•R1(R1/VINmustnotexceedISET)

DS005697-9

*Useminimumvaluerequiredtoensurestabilityofprotecteddevice.Thisminimizesinrushcurrenttoadirectshort.

SchematicDiagram

DS005697-11

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LM134/LM234/LM334

PhysicalDimensions

inches

(millimeters)unlessotherwisenoted

OrderNumberLM134H,LM234HorLM334H

NSPackageNumberH03H

www.national.com12

LM134/LM234/LM334

PhysicalDimensions

inches

(millimeters)unlessotherwisenoted(Continued)

SOPackage(M)

OrderNumberLM334M,LM334MX,

LM334SMorLM334SMXNSPackageNumberM08A

OrderNumberLM334Z,LM234Z-3orLM234Z-6

NSPackageNumberZ03A

13www.national.com

LM134/LM234/LM3343-TerminalAdjustableCurrentSources

Notes

LIFESUPPORTPOLICY

NATIONAL’SPRODUCTSARENOTAUTHORIZEDFORUSEASCRITICALCOMPONENTSINLIFESUPPORTDEVICESORSYSTEMSWITHOUTTHEEXPRESSWRITTENAPPROVALOFTHEPRESIDENTANDGENERALCOUNSELOFNATIONALSEMICONDUCTORCORPORATION.

Asusedherein:1.Lifesupportdevicesorsystemsaredevicesorsystemswhich,(a)areintendedforsurgicalimplantintothebody,or(b)supportorsustainlife,andwhosefailuretoperformwhenproperlyusedinaccordancewithinstructionsforuseprovidedinthelabeling,canbereasonablyexpectedtoresultinasignificantinjurytotheuser.

NationalSemiconductorCorporationAmericas

Tel:1-800-272-9959Fax:1-800-737-7018Email:[email protected]

www.national.com

NationalSemiconductorEurope

Fax:+49(0)180-5308586Email:[email protected]

DeutschTel:+49(0)6995086208EnglishTel:+44(0)8702402171FrançaisTel:+33(0)141918790

2.Acriticalcomponentisanycomponentofalifesupportdeviceorsystemwhosefailuretoperformcanbereasonablyexpectedtocausethefailureofthelifesupportdeviceorsystem,ortoaffectitssafetyoreffectiveness.

NationalSemiconductorAsiaPacificCustomerResponseGroupTel:65-2544466Fax:65-2504466

Email:[email protected]

NationalSemiconductorJapanLtd.

Tel:81-3-5639-7560Fax:81-3-5639-7507

Nationaldoesnotassumeanyresponsibilityforuseofanycircuitrydescribed,nocircuitpatentlicensesareimpliedandNationalreservestherightatanytimewithoutnoticetochangesaidcircuitryandspecifications.

LM134/LM234/LM3343-TerminalAdjustableCurrentSources

March2000

LM134/LM234/LM334

3-TerminalAdjustableCurrentSources

GeneralDescription

The

Applicationsforthecurrentsourcesincludebiasnetworks,surgeprotection,lowpowerreference,rampgeneration,

TheLM134isguaranteedoveratemperaturerangeof−55˚Cto+125˚C,theLM234from−25˚Cto+100˚CandtheLM334from0˚Cto+70˚C.ThesedevicesareavailableinTO-46hermetic,TO-92andSO-8plasticpackages.

Features

nnnnnn

Operatesfrom1Vto40V0.02%/Vcurrentregulation

Programmablefrom1µAto10mATrue2-terminaloperation

Availableasfullyspecifiedtemperaturesensor±3%initialaccuracy

ConnectionDiagrams

SO-8

SurfaceMountPackage

SO-8AlternativePinoutSurfaceMountPackage

TO-46

MetalCanPackage

DS005697-24

DS005697-12

DS005697-25

OrderNumberLM334Mor

LM334MX

SeeNSPackageNumberM08A

OrderNumberLM334SMor

LM334SMX

SeeNSPackageNumberM08A

VPiniselectricallyconnectedtocase.

−

BottomView

OrderNumberLM134H,LM234HorLM334HSeeNSPackageNumberH03H

TO-92PlasticPackage

DS005697-10

BottomView

OrderNumberLM334Z,LM234Z-3orLM234Z-6

SeeNSPackageNumberZ03A

2000NationalSemiconductorCorporationDS005697www.national.com

LM134/LM234/LM334

AbsoluteMaximumRatings

(Note1)

IfMilitary/Aerospacespecifieddevicesarerequired,pleasecontacttheNationalSemiconductorSalesOffice/Distributorsforavailabilityandspecifications.V+toV−ForwardVoltageLM134/LM234/LM334LM234-3/LM234-6+

VtoV−ReverseVoltageRPintoV−VoltageSetCurrent

PowerDissipation

ESDSusceptibility(Note6)

OperatingTemperatureRange(Note5)LM134

40V30V20V5V10mA400mW2000V

−55˚Cto+125˚C

LM234/LM234-3/LM234-6−25˚Cto+100˚CLM3340˚Cto+70˚CSolderingInformation

TO-92Package(10sec.)260˚CTO-46Package(10sec.)300˚CSOPackage

VaporPhase(60sec.)215˚CInfrared(15sec.)220˚CSeeAN-450“SurfaceMountingMethodsandTheirEffectonProductReliability”(AppendixD)forothermethodsofsol-deringsurfacemountdevices.

ElectricalCharacteristics(Note2)

Parameter

SetCurrentError,V+=2.5V,(Note3)

RatioofSetCurrenttoBiasCurrent

MinimumOperatingVoltage

Conditions

Min

10µA≤ISET≤1mA1mA

1mA

AverageChangeinSetCurrentwithInputVoltage

2µA≤ISET≤1mA1.5≤V+≤5V5V≤V≤40V1mA

TemperatureDependenceofSetCurrent(Note4)EffectiveShuntCapacitance

Note1:.“AbsoluteMaximumRatings”indicatelimitsbeyondwhichdamagetothedevicemayoccur.OperatingRatingsindicateconditionsforwhichthedeviceisfunctional,butdonotguaranteespecificperformancelimits.

Note2:Unlessotherwisespecified,testsareperformedatTj=25˚Cwithpulsetestingsothatjunctiontemperaturedoesnotchangeduringtest

Note4:ISETisdirectlyproportionaltoabsolutetemperature(˚K).ISETatanytemperaturecanbecalculatedfrom:ISET=Io(T/To)whereIoisISETmeasuredatTo(˚K).

Note5:Forelevatedtemperatureoperation,TJmaxis:

LM134/LM234

Typ

Max358

1814180.80.91.00.020.010.030.02

0.96T

1.04T

0.96T

0.050.032323

14Min

LM334Typ

Max6812

1814180.80.91.00.020.010.030.02T

1.04T0.10.052626

Units%%%

VVV%/V%/V%/V%/V

25µA≤ISET≤1mA

LM134LM234LM334

ThermalResistanceθja(JunctiontoAmbient)θjc(JunctiontoCase)

150˚C125˚C100˚C

TO-92

180˚C/W(0.4"leads)160˚C/W(0.125"leads)

N/A

32˚C/W

80˚C/W

TO-46440˚C/W

SO-8165˚C/W

Note6:Humanbodymodel,100pFdischargedthrougha1.5kΩresistor.

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LM134/LM234/LM334

ElectricalCharacteristics(Note

Parameter

SetCurrentError,V+=2.5V,(Note3)

EquivalentTemperatureErrorRatioofSetCurrenttoBiasCurrent

MinimumOperatingVoltageAverageChangeinSetCurrentwithInputVoltage

TemperatureDependenceofSetCurrent(Note4)andEquivalentSlopeErrorEffectiveShuntCapacitance

100µAISET≤1mA100µA≤ISET≤1mA

1.5≤V+≤5V5V≤V+≤30V100µA≤ISET≤1mA

0.98T

0.020.01T

0.050.031.02T

0.97T

0.020.01T

0.010.051.03T

%/V%/V

0.9

100µA≤ISET≤1mA

Conditions

Min

100µA≤ISET≤1mATJ=25˚

LM234-3Typ

Max

Min

LM234-6Typ

Max

Units

±1±2

±3

±6

˚C

±2

±3

%pF

3www.national.com

LM134/LM234/LM334

TypicalPerformanceCharacteristics

OutputImpedance

MaximumSlewRateLinearOperation

DS005697-30

DS005697-31

Start-UpTransientResponse

DS005697-32

DS005697-33

VoltageAcrossRSET(VR)CurrentNoise

DS005697-34

DS005697-35

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LM134/LM234/LM334

TypicalPerformanceCharacteristics

Turn-OnVoltage

(Continued)

RatioofISETtoIBIAS

DS005697-29

DS005697-3

ApplicationHints

ThetotalcurrentthroughtheLM134(ISET)isthesumofthecurrentgoingthroughtheSETresistor(IR)andtheLM134’sbiascurrent(IBIAS),asshowninFigure1.

wherenistheratioofISETtoIBIASasspecifiedintheElec-tricalCharacteristicsSectionandshowninthegraph.Sincenistypically18for2µA≤ISET≤1mA,theequationcanbefurthersimplifiedto

formostsetcurrents.

SLEWRATE

THERMALEFFECTS

SHUNTCAPACITANCE

DS005697-27

FIGURE1.BasicCurrentSource

Since(foragivensetcurrent)IBIASissimplyapercentageofISET,theequationcanberewritten

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LM134/LM234/LM334

ApplicationHints

NOISE

(Continued)

APPLICATIONASAZEROTEMPERATURECOEFFICENTCURRENTSOURCE

DS005697-28

FIGURE3.ZeroTempcoCurrentSource

Thesetcurrent(ISET)isthesumofI1andI2,eachcontribut-ingapproximately50%ofthesetcurrent,andIBIAS.IBIASisusuallyincludedintheI1termbyincreasingtheVRvalueusedforcalculationsby5.9%.(SeeCALCULATINGRSET.)

DS005697-4

FIGURE2.GainAdjustment

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LM134/LM234/LM334

ApplicationHints

(Continued)

A1mALM134currentsourcewithnotemperaturecompen-sationwouldhaveasetresistorof68Ωandaresultingtempcoof

Soevenifthediode’stempcovariesasmuchas±4%fromitsestimatedvalue,thecircuitstilleliminates98%oftheLM134’sinherenttempco.

TypicalApplications

GroundReferredFahrenheitThermometer

ThevaluesofR1andR2canbechangedtostandard1%re-sistorvalues(R1=133ΩandR2=1.33kΩ)withlessthana0.75%error.

Iftheforwardvoltagedropofthediodewas0.65Vinsteadoftheestimateof0.6V(anerrorof8%),theactualsetcurrentwillbe

DS005697-15

*SelectR3=VREF/583µA.VREFmaybeanystablepositivevoltage≥2V

TrimR3tocalibrate

anerroroflessthan5%.

7www.national.com

TypicalApplications

(Continued)

LowOutputImpedance

Thermometer

TerminatingRemoteSensorforVoltage

Output

DS005697-6

*OutputimpedanceoftheLM134atthe“R”pinis

approximately

DS005697-14

LM134/LM234/LM334

TypicalApplications

(Continued)

LowInputVoltageReferenceDriver

MicropowerBias

DS005697-17

DS005697-18

RampGenerator

DS005697-19

9www.national.com

LM134/LM234/LM334

TypicalApplications

(Continued)

1.2VRegulatorwith1.8VMinimumInput

1.2VReferenceOperateson10µAand2V

DS005697-20

*SelectratioofR1toR2toobtainzerotemperaturedrift

DS005697-7

*SelectratioofR1toR2forzerotemperaturedrift

ZenerBiasingAlternateTrimmingTechniqueBufferforPhotoconductiveCell

DS005697-51

DS005697-49

DS005697-50

*For±10%adjustment,selectRSET10%high,andmakeR1≈3RSET

FETCascodingforLowCapacitanceand/orUltraHighOutputImpedance

DS005697-21

*SelectQ1orQ2toensureatleast1VacrosstheLM134.Vp(1−ISET/IDSS)≥1.2V.

DS005697-22

www.national.com10

LM134/LM234/LM334

TypicalApplications

(Continued)

In-LineCurrentLimiter

GeneratingNegativeOutputImpedance

DS005697-23

*ZOUT≈−16•R1(R1/VINmustnotexceedISET)

DS005697-9

*Useminimumvaluerequiredtoensurestabilityofprotecteddevice.Thisminimizesinrushcurrenttoadirectshort.

SchematicDiagram

DS005697-11

11www.national.com

LM134/LM234/LM334

PhysicalDimensions

inches

(millimeters)unlessotherwisenoted

OrderNumberLM134H,LM234HorLM334H

NSPackageNumberH03H

www.national.com12

LM134/LM234/LM334

PhysicalDimensions

inches

(millimeters)unlessotherwisenoted(Continued)

SOPackage(M)

OrderNumberLM334M,LM334MX,

LM334SMorLM334SMXNSPackageNumberM08A

OrderNumberLM334Z,LM234Z-3orLM234Z-6

NSPackageNumberZ03A

13www.national.com

LM134/LM234/LM3343-TerminalAdjustableCurrentSources

Notes

LIFESUPPORTPOLICY

NATIONAL’SPRODUCTSARENOTAUTHORIZEDFORUSEASCRITICALCOMPONENTSINLIFESUPPORTDEVICESORSYSTEMSWITHOUTTHEEXPRESSWRITTENAPPROVALOFTHEPRESIDENTANDGENERALCOUNSELOFNATIONALSEMICONDUCTORCORPORATION.

NationalSemiconductorCorporationAmericas

Tel:1-800-272-9959Fax:1-800-737-7018Email:[email protected]

www.national.com

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Fax:+49(0)180-5308586Email:[email protected]

DeutschTel:+49(0)6995086208EnglishTel:+44(0)8702402171FrançaisTel:+33(0)141918790

2.Acriticalcomponentisanycomponentofalifesupportdeviceorsystemwhosefailuretoperformcanbereasonablyexpectedtocausethefailureofthelifesupportdeviceorsystem,ortoaffectitssafetyoreffectiveness.

NationalSemiconductorAsiaPacificCustomerResponseGroupTel:65-2544466Fax:65-2504466

Email:[email protected]

NationalSemiconductorJapanLtd.

Tel:81-3-5639-7560Fax:81-3-5639-7507

Nationaldoesnotassumeanyresponsibilityforuseofanycircuitrydescribed,nocircuitpatentlicensesareimpliedandNationalreservestherightatanytimewithoutnoticetochangesaidcircuitryandspecifications.

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