2024年11月1日发(作者：税运珹)

LM134/LM234/LM334

3-Terminal

Adjustable

Current

Sources

May1998

LM134/LM234/LM334

3-TerminalAdjustableCurrentSources

GeneralDescription

TheLM134/LM234/LM334are3-terminaladjustablecurrent

sourcesfeaturing10,000:1rangeinoperatingcurrent,excel-

lentcurrentregulationandawidedynamicvoltagerangeof

tisestablishedwithoneexternalresistor

lcurrentaccuracyis

±

3%.TheLM134/LM234/LM334aretruefloatingcurrent

-

tion,reverseappliedvoltagesofupto20Vwilldrawonlya

fewdozenmicroamperesofcurrent,allowingthedevicesto

actasbotharectifierandcurrentsourceinACapplications.

Thesensevoltageusedtoestablishoperatingcurrentinthe

LM134is64mVat25˚Candisdirectlyproportionaltoabso-

lutetemperature(˚K).Thesimplestoneexternalresistor

connection,then,generatesacurrentwith≈+0.33%/˚Ctem-

iftoperationcanbeobtained

byaddingoneextraresistorandadiode.

Applicationsforthecurrentsourcesincludebiasnetworks,

surgeprotection,lowpowerreference,rampgeneration,

LEDdriver,134-3/

LM234-3andLM134-6/LM234-6arespecifiedastruetem-

peraturesensorswithguaranteedinitialaccuracyof

±

3˚C

and

±

6˚C,evicesareidealinremote

senseapplicationsbecauseseriesresistanceinlongwire

tion,only2wiresare

required.

TheLM134isguaranteedoveratemperaturerangeof

−55˚Cto+125˚C,theLM234from−25˚Cto+100˚Candthe

LM334from0˚Cto+70˚evicesareavailablein

TO-46hermetic,TO-92andSO-8plasticpackages.

Features

n

n

n

n

n

n

Operatesfrom1Vto40V

0.02%/Vcurrentregulation

Programmablefrom1µAto10mA

True2-terminaloperation

Availableasfullyspecifiedtemperaturesensor

±

3%initialaccuracy

ConnectionDiagrams

SO-8

SurfaceMountPackage

SO-8AlternativePinout

SurfaceMountPackage

TO-46

MetalCanPackage

DS005697-25

DS005697-24

OrderNumberLM334M

SeeNSPackageNumberM08A

OrderNumberLM334SM

SeeNSPackageNumberM08A

DS005697-10

BottomView

OrderNumberLM334Z,LM234Z-3orLM234Z-6

SeeNSPackageNumberZ03A

©

AbsoluteMaximumRatings

(Note1)

IfMilitary/Aerospacespecifieddevicesarerequired,

pleasecontacttheNationalSemiconductorSalesOffice/

Distributorsforavailabilityandspecifications.

V

+

toV

−

ForwardVoltage

LM134/LM234/LM334

LM134-3/LM134-6/LM234-3/LM234-6

+

V

toV

−

ReverseVoltage

RPintoV

−

Voltage

SetCurrent

PowerDissipation

ESDSusceptibility(Note6)

OperatingTemperatureRange(Note5)

LM134/LM134-3/LM134-6

40V

30V

20V

5V

10mA

400mW

2000V

−55˚Cto+125˚C

LM234/LM234-3/LM234-6−25˚Cto+100˚C

LM3340˚Cto+70˚C

SolderingInformation

TO-92Package(10sec.)260˚C

TO-46Package(10sec.)300˚C

SOPackage

VaporPhase(60sec.)215˚C

Infrared(15sec.)220˚C

SeeAN-450“SurfaceMountingMethodsandTheirEffecton

ProductReliability”(AppendixD)forothermethodsofsol-

deringsurfacemountdevices.

ElectricalCharacteristics

(Note2)

Parameter

SetCurrentError,V

(Note3)

RatioofSetCurrentto

BiasCurrent

MinimumOperatingVoltage

+

=

Conditions

Min

2.5V,10µA≤I

SET

≤1mA

1mA

<

I

SET

≤5mA

2µA≤I

SET

<

10µA

100µA≤I

SET

≤1mA

1mA≤I

SET

≤5mA

2µA≤I

SET

≤100µA

2µA≤I

SET

≤100µA

100µA

<

I

SET

≤1mA

1mA

<

I

SET

≤5mA

14

LM134/LM234

TypMax

3

5

8

18

14

18

0.8

0.9

1.0

0.02

0.01

0.03

0.02

0.96TT

15

1.04T0.96T

0.05

0.03

23

2314

Min

LM334

TypMax

6

8

12

18

14

18

0.8

0.9

1.0

0.02

0.01

0.03

0.02

T

15

1.04T

0.1

0.05

26

26

Units

%

%

%

V

V

V

%/V

%/V

%/V

%/V

AverageChangeinSetCurrent

withInputVoltage

2µA≤I

SET

≤1mA

1.5≤V

+

≤5V

5V≤V

≤40V

1mA

<

I

SET

≤5mA

1.5V≤V≤5V

5V≤V≤40V

+

TemperatureDependenceof

SetCurrent(Note4)

EffectiveShuntCapacitance

25µA≤I

SET

≤1mA

pF

Note1:.“AbsoluteMaximumRatings”ingRatingsindicateconditionsforwhichthedeviceis

functional,butdonotguaranteespecificperformancelimits.

Note2:Unlessotherwisespecified,testsareperformedatT

j

=

25˚Cwithpulsetestingsothatjunctiontemperaturedoesnotchangeduringtest

Note3:SetcurrentisthecurrentflowingintotheV

+

Basic2-TerminalCurrentSourcecircuitshownonthefirstpageofthisdatasheet.I

SET

isdetermined

bythefollowingformula:I

SET

=

67.7mV/R

SET

(

@

25˚C).Setcurrenterrorisexpressedasapercentdeviationfromthisamount.I

SET

increasesat0.336%/˚C

@

T

j

=

25˚C(227µV/˚C).

Note4:I

SET

isdirectlyproportionaltoabsolutetemperature(˚K).I

SET

atanytemperaturecanbecalculatedfrom:I

SET

=

I

o

(T/T

o

)whereI

o

isI

SET

measuredatT

o

(˚K).

Note5:Forelevatedtemperatureoperation,T

j

maxis:

LM134

LM234

LM334

ThermalResistance

θ

ja

(JunctiontoAmbient)

θ

jc

(JunctiontoCase)

150˚C

125˚C

100˚C

TO-92

180˚C/W(0.4"leads)

160˚C/W(0.125"leads)

N/A32˚C/W80˚C/W

TO-46

440˚C/W

SO-8

165˚C/W

Note6:Humanbodymodel,100pFdischargedthrougha1.5kΩresistor.

2

ElectricalCharacteristics

(Note2)

Parameter

SetCurrentError,V

(Note3)

EquivalentTemperatureError

RatioofSetCurrentto

BiasCurrent

MinimumOperatingVoltage

AverageChangeinSetCurrent

withInputVoltage

TemperatureDependenceof

SetCurrent(Note4)and

EquivalentSlopeError

EffectiveShuntCapacitance15

100µAI

SET

≤1mA

100µA≤I

SET

≤1mA

1.5≤V

+

≤5V

5V≤V

≤30V

100µA≤I

SET

≤1mA0.98T

+

+

=

Conditions

100µA≤I

SET

≤1mA

T

j

=

25˚

100µA≤I

SET

≤1mA

LM134-3,LM234-3

MinTypMax

LM134-6,LM234-6

MinTypMax

Units

%

˚C

2.5V,

±

1

±

3

1418

0.9

0.02

0.01

T

0.05

0.03

1.02T0.97T

261418

0.9

0.02

0.01

T

±

2

±

6

26

V

0.01

0.05

1.03T

%/V

%/V

±

2

15

±

3

%

pF

TypicalPerformanceCharacteristics

OutputImpedance

MaximumSlewRate

LinearOperation

Start-Up

DS005697-30

DS005697-31

DS005697-32

TransientResponseVoltageAcrossR

SET

(V

R

)CurrentNoise

DS005697-33DS005697-34

DS005697-35

TypicalPerformanceCharacteristics

Turn-OnVoltage

(Continued)

RatioofI

SET

toI

BIAS

DS005697-29

DS005697-3

ApplicationHints

TheLM134hasbeendesignedforeaseofapplication,buta

generaldiscussionofdesignfeaturesispresentedhereto

familiarizethedesignerwithdevicecharacteristicswhich

ncludetheeffects

ofslewing,powerdissipation,capacitance,noise,andcon-

tactresistance.

CALCULATINGR

SET

ThetotalcurrentthroughtheLM134(I

SET

)isthesumofthe

currentgoingthroughtheSETresistor(I

R

)andtheLM134’s

biascurrent(I

BIAS

),asshownin

Figure1

.

wherenistheratioofI

SET

toI

BIAS

asspecifiedintheElec-

nistypically18for2µA≤I

SET

≤1mA,theequationcanbe

furthersimplifiedto

formostsetcurrents.

SLEWRATE

Atslewratesaboveagiventhreshold(seecurve),the

wing

rateatwhichthisoccursisdirectlyproportionaltoI

SET

.At

I

SET

=

10µA,maximumdV/dtis0.01V/µs;atI

SET

=

1mA,

thelimitis1V/µtesabovethelimitdonotharmthe

LM134,orcauselargecurrentstoflow.

THERMALEFFECTS

Internalheatingcanhaveasignificanteffectoncurrentregu-

lationforI

SET

greaterthan100µmple,each1Vin-

creaseacrosstheLM134atI

SET

=

1mAwillincreasejunc-

tiontemperatureby≈0.4˚current(I

SET

)

hasatemperaturecoefficientof≈0.33%/˚C,sothechangein

currentduetotemperaturerisewillbe(0.4)(0.33)

=

0.132%.

Thisisa10:1degradationinregulationcomparedtotrue

leffects,therefore,mustbetaken

intoaccountwhenDCregulationiscriticalandI

SET

exceeds

100µnkingoftheTO-46packageortheTO-92

leadscanreducethiseffectbymorethan3:1.

SHUNTCAPACITANCE

Incertainapplications,the15pFshuntcapacitanceofthe

LM134mayhavetobereduced,eitherbecauseofloading

problemsorbecauseitlimitstheACoutputimpedanceofthe

nbeeasilyaccomplishedbybuffering

canreducecapacitancetolessthan3pFandimproveregu-

acteristics

(withtheexceptionofminimuminputvoltage),arenotaf-

fected.

DS005697-27

urrentSource

Agraphshowingtheratioofthesetwocurrentsissupplied

underRatioofI

SET

toI

BIAS

intheTypicalPerformance

rentflowingthroughR

SET

is

determinedbyV

R

,whichisapproximately214µV/˚K(64mV/

298˚K

z

214µV/˚K).

Since(foragivensetcurrent)I

BIAS

issimplyapercentageof

I

SET

,theequationcanberewritten

4

ApplicationHints

NOISE

(Continued)

APPLICATIONASAZEROTEMPERATURE

COEFFICENTCURRENTSOURCE

AddingadiodeandaresistortothestandardLM134con-

figurationcancancelthetemperature-dependentcharacter-

cuitshownin

Figure3

balances

thepositivetempcooftheLM134(about+0.23mV/˚C)with

thenegativetempcoofaforward-biasedsilicondiode(about

−2.5mV/˚C).

CurrentnoisegeneratedbytheLM134isapproximately4

M134isusedas

anactiveloadforatransistoramplifier,inputreferrednoise

cases,thisisac-

ceptableandasinglestageamplifiercanbebuiltwithavolt-

agegainexceeding2000.

LEADRESISTANCE

Thesensevoltagewhichdeterminesoperatingcurrentofthe

level,thermocoupleor

leadresistanceeffectsshouldbeminimizedbylocatingthe

-

sonly0.7Ωcontact

resistancetoreduceoutputcurrentby1%atthe1mAlevel.

SENSINGTEMPERATURE

TheLM134makesanidealremotetemperaturesensorbe-

causeitscurrentmodeoperationdoesnotloseaccuracy

currentisdirectlyproportionalto

absolutetemperatureindegreesKelvin,accordingtothefol-

lowingformula:

CalibrationoftheLM134isgreatlysimplifiedbecauseofthe

factthatmostoftheinitialinaccuracyisduetoagainterm

(slopeerror)ansthatacalibration

consistingofagainadjustmentonlywilltrimbothslopeand

tion,gainadjustmentisaone

pointtrimbecausetheoutputoftheLM134extrapolatesto

zeroat0˚K,independentofR

SET

oranyinitialinaccuracy.

DS005697-28

mpcoCurrentSource

Thesetcurrent(I

SET

)isthesumofI

1

andI

2

,eachcontribut-

ingapproximately50%ofthesetcurrent,andI

BIAS

.I

BIAS

is

usuallyincludedintheI

1

termbyincreasingtheV

R

value

usedforcalculationsby5.9%.(SeeCALCULATINGR

SET

.)

Thefirststepistominimizethetempcoofthecircuit,using

pleisgivenusingavalueof

+227µV/˚CasthetempcooftheLM134(whichincludesthe

I

BIAS

component),and−2.5mV/˚Casthetempcoofthedi-

ode(forbestresults,thisvalueshouldbedirectlymeasured

orobtainedfromthemanufacturerofthediode).

DS005697-4

justment

ThispropertyoftheLM134isillustratedintheaccompanying

a'b'c'rimdoneatT2willmove

theoutputfrombtob'andwillsimultaneouslycorrectthe

gaintrimcanbedoneonR

SET

orontheloadresistorused

rroraftertrimwillnormally

belessthan

±

1%.Tomaintainthisaccuracy,however,alow

temperaturecoefficientresistormustbeusedforR

SET

.

A33ppm/˚CdriftofR

SET

willgivea1%slopeerrorbecause

theresistorwillnormallyseeaboutthesametemperature

tingR

SET

fromtheLM134

requires3wiresandhasleadresistanceproblems,soisnot

ilmresistorswithlessthan

20ppm/˚undresistors

mayalsobeusedwherebeststabilityisrequired.

5

WiththeR

1

toR

2

ratiodetermined,valuesforR

1

andR

2

formulaforcalculatingthesetcurrentatT

=

25˚Cisshown

below,followedbyanexamplethatassumestheforward

voltagedropacrossthediode(V

D

)is0.6V,thevoltage

acrossR

1

is67.7mV(64mV+5.9%toaccountforI

BIAS

),

andR

2

/R

1

=

10(fromthepreviouscalculations).

ApplicationHints

(Continued)

Iftheestimateforthetempcoofthediode’sforwardvoltage

dropwasoff,thetempcocancellationisstillreasonablyef-

thetempcoofthediodeis2.6mV/˚Cinstead

of2.5mV/˚C(anerrorof4%).Thetempcoofthecircuitis

now:

ThiscircuitwilleliminatemostoftheLM134’stemperature

coefficient,anditdoesagoodjobeveniftheestimatesofthe

diode’scharacteristicsarenotaccurate(asthefollowingex-

amplewillshow).Forlowesttempcowithaspecificdiodeat

thedesiredI

SET

,however,thecircuitshouldbebuiltand

easuredtempcoofI

SET

is

positive,R

2

esultingtempcois

negative,R

2

ommendeddiode

foruseinthiscircuitisthe1N457becauseitstempcoiscen-

teredat11timesthetempcooftheLM134,allowingR

2

=

10

R

1

.Youcanalsousethiscircuittocreateacurrentsource

withnon-zerotempcosbysettingthetempcocomponentof

thetempcoequationtothedesiredvalueinsteadof0.

EXAMPLE:A1mA,Zero-TempcoCurrentSource

First,solveforR

1

andR

2

:

A1mALM134currentsourcewithnotemperaturecompen-

sationwouldhaveasetresistorof68Ωandaresulting

tempcoof

Soevenifthediode’stempcovariesasmuchas

±

4%from

itsestimatedvalue,thecircuitstilleliminates98%ofthe

LM134’sinherenttempco.

TypicalApplications

GroundReferredFahrenheitThermometer

ThevaluesofR

1

andR

2

canbechangedtostandard1%re-

sistorvalues(R

1

=

133ΩandR

2

=

1.33kΩ)withlessthana

0.75%error.

Iftheforwardvoltagedropofthediodewas0.65Vinsteadof

theestimateof0.6V(anerrorof8%),theactualsetcurrent

willbe

DS005697-15

*

SelectR3

=

V

REF

/583µA.V

REF

maybeanystablepositivevoltage≥2V

TrimR3tocalibrate

anerroroflessthan5%.

6

Applications

(Continued)

TerminatingRemoteSensorforVoltageOutput

DS005697-14

LowOutputImpedanceThermometer

DS005697-6

*OutputimpedanceoftheLM134atthe“R”pinisapproximately

Typical

TypicalApplications

(Continued)

LowInputVoltageReferenceDriver

MicropowerBias

DS005697-17

DS005697-18

RampGenerator

DS005697-19

8

TypicalApplications

(Continued)

1.2VRegulatorwith1.8VMinimumInput

1.2VReferenceOperateson10µAand2V

DS005697-20

*SelectratioofR1toR2toobtainzerotemperaturedrift

DS005697-7

*SelectratioofR1toR2forzerotemperaturedrift

ZenerBiasing

AlternateTrimmingTechnique

BufferforPhotoconductiveCell

DS005697-51

DS005697-49

DS005697-50

*For

±

10%adjustment,selectR

SET

10%high,andmakeR1≈3R

SET

FETCascodingforLowCapacitanceand/orUltraHighOutputImpedance

DS005697-21

*SelectQ1orQ2toensureatleast1VacrosstheLM134.V

p

(1−

I

SET

/I

DSS

)≥1.2V.

DS005697-22

TypicalApplications

(Continued)

In-LineCurrentLimiterGeneratingNegativeOutputImpedance

DS005697-23

*Z

OUT

≈−16

•

R1(R1/V

IN

mustnotexceedI

SET

)

DS005697-9

*

minimizesinrushcurrenttoadirectshort.

SchematicDiagram

DS005697-11

10

11

PhysicalDimensions

inches(millimeters)unlessotherwisenoted

OrderNumberLM134H,LM134H-3,

LM134H-6,LM234HorLM334H

NSPackageNumberH03H

12

PhysicalDimensions

inches(millimeters)unlessotherwisenoted(Continued)

SOPackage(M)

OrderNumberLM334MorLM334SM

NSPackageNumberM08A

OrderNumberLM334Z,LM234Z-3orLM234Z-6

NSPackageNumberZ03A

L

M

1

3

4

/

L

M

2

3

4

/

L

M

3

3

4

3

-

T

e

r

m

i

n

a

l

A

d

j

u

s

t

a

b

l

e

C

u

r

r

e

n

t

S

o

u

r

c

e

s

LIFESUPPORTPOLICY

NATIONAL’SPRODUCTSARENOTAUTHORIZEDFORUSEASCRITICALCOMPONENTSINLIFESUPPORTDE-

VICESORSYSTEMSWITHOUTTHEEXPRESSWRITTENAPPROVALOFTHEPRESIDENTOFNATIONALSEMI-

herein:

calcomponentisanycomponentofalifesupport

pportdevicesorsystemsaredevicesorsys-

deviceorsystemwhosefailuretoperformcanberea-

temswhich,(a)areintendedforsurgicalimplantinto

sonablyexpectedtocausethefailureofthelifesupport

thebody,or(b)supportorsustainlife,andwhosefail-

deviceorsystem,ortoaffectitssafetyoreffectiveness.

uretoperformwhenproperlyusedinaccordance

withinstructionsforuseprovidedinthelabeling,can

bereasonablyexpectedtoresultinasignificantinjury

totheuser.

NationalSemiconductor

Corporation

Americas

Tel:1-800-272-9959

Fax:1-800-737-7018

Email:support@

NationalSemiconductor

Europe

Fax:+49(0)180-5308586

Email:t@

DeutschTel:+49(0)180-5308585

EnglishTel:+49(0)180-5327832

FrançaisTel:+49(0)180-5329358

ItalianoTel:+49(0)180-5341680

NationalSemiconductor

AsiaPacificCustomer

ResponseGroup

Tel:65-2544466

Fax:65-2504466

Email:t@

NationalSemiconductor

JapanLtd.

Tel:81-3-5639-7560

Fax:81-3-5639-7507

Nationaldoesnotassumeanyresponsibilityforuseofanycircuitrydescribed,nocircuitpatentlicensesareimpliedandNationalreservestherightatanytimewithoutnoticetochangesaidcircuitryandspecifications.

2024年11月1日发(作者：税运珹)

LM134/LM234/LM334

3-Terminal

Adjustable

Current

Sources

May1998

LM134/LM234/LM334

3-TerminalAdjustableCurrentSources

GeneralDescription

TheLM134/LM234/LM334are3-terminaladjustablecurrent

sourcesfeaturing10,000:1rangeinoperatingcurrent,excel-

lentcurrentregulationandawidedynamicvoltagerangeof

tisestablishedwithoneexternalresistor

lcurrentaccuracyis

±

3%.TheLM134/LM234/LM334aretruefloatingcurrent

-

tion,reverseappliedvoltagesofupto20Vwilldrawonlya

fewdozenmicroamperesofcurrent,allowingthedevicesto

actasbotharectifierandcurrentsourceinACapplications.

Thesensevoltageusedtoestablishoperatingcurrentinthe

LM134is64mVat25˚Candisdirectlyproportionaltoabso-

lutetemperature(˚K).Thesimplestoneexternalresistor

connection,then,generatesacurrentwith≈+0.33%/˚Ctem-

iftoperationcanbeobtained

byaddingoneextraresistorandadiode.

Applicationsforthecurrentsourcesincludebiasnetworks,

surgeprotection,lowpowerreference,rampgeneration,

LEDdriver,134-3/

LM234-3andLM134-6/LM234-6arespecifiedastruetem-

peraturesensorswithguaranteedinitialaccuracyof

±

3˚C

and

±

6˚C,evicesareidealinremote

senseapplicationsbecauseseriesresistanceinlongwire

tion,only2wiresare

required.

TheLM134isguaranteedoveratemperaturerangeof

−55˚Cto+125˚C,theLM234from−25˚Cto+100˚Candthe

LM334from0˚Cto+70˚evicesareavailablein

TO-46hermetic,TO-92andSO-8plasticpackages.

Features

n

n

n

n

n

n

Operatesfrom1Vto40V

0.02%/Vcurrentregulation

Programmablefrom1µAto10mA

True2-terminaloperation

Availableasfullyspecifiedtemperaturesensor

±

3%initialaccuracy

ConnectionDiagrams

SO-8

SurfaceMountPackage

SO-8AlternativePinout

SurfaceMountPackage

TO-46

MetalCanPackage

DS005697-25

DS005697-24

OrderNumberLM334M

SeeNSPackageNumberM08A

OrderNumberLM334SM

SeeNSPackageNumberM08A

DS005697-10

BottomView

OrderNumberLM334Z,LM234Z-3orLM234Z-6

SeeNSPackageNumberZ03A

©

AbsoluteMaximumRatings

(Note1)

IfMilitary/Aerospacespecifieddevicesarerequired,

pleasecontacttheNationalSemiconductorSalesOffice/

Distributorsforavailabilityandspecifications.

V

+

toV

−

ForwardVoltage

LM134/LM234/LM334

LM134-3/LM134-6/LM234-3/LM234-6

+

V

toV

−

ReverseVoltage

RPintoV

−

Voltage

SetCurrent

PowerDissipation

ESDSusceptibility(Note6)

OperatingTemperatureRange(Note5)

LM134/LM134-3/LM134-6

40V

30V

20V

5V

10mA

400mW

2000V

−55˚Cto+125˚C

LM234/LM234-3/LM234-6−25˚Cto+100˚C

LM3340˚Cto+70˚C

SolderingInformation

TO-92Package(10sec.)260˚C

TO-46Package(10sec.)300˚C

SOPackage

VaporPhase(60sec.)215˚C

Infrared(15sec.)220˚C

SeeAN-450“SurfaceMountingMethodsandTheirEffecton

ProductReliability”(AppendixD)forothermethodsofsol-

deringsurfacemountdevices.

ElectricalCharacteristics

(Note2)

Parameter

SetCurrentError,V

(Note3)

RatioofSetCurrentto

BiasCurrent

MinimumOperatingVoltage

+

=

Conditions

Min

2.5V,10µA≤I

SET

≤1mA

1mA

<

I

SET

≤5mA

2µA≤I

SET

<

10µA

100µA≤I

SET

≤1mA

1mA≤I

SET

≤5mA

2µA≤I

SET

≤100µA

2µA≤I

SET

≤100µA

100µA

<

I

SET

≤1mA

1mA

<

I

SET

≤5mA

14

LM134/LM234

TypMax

3

5

8

18

14

18

0.8

0.9

1.0

0.02

0.01

0.03

0.02

0.96TT

15

1.04T0.96T

0.05

0.03

23

2314

Min

LM334

TypMax

6

8

12

18

14

18

0.8

0.9

1.0

0.02

0.01

0.03

0.02

T

15

1.04T

0.1

0.05

26

26

Units

%

%

%

V

V

V

%/V

%/V

%/V

%/V

AverageChangeinSetCurrent

withInputVoltage

2µA≤I

SET

≤1mA

1.5≤V

+

≤5V

5V≤V

≤40V

1mA

<

I

SET

≤5mA

1.5V≤V≤5V

5V≤V≤40V

+

TemperatureDependenceof

SetCurrent(Note4)

EffectiveShuntCapacitance

25µA≤I

SET

≤1mA

pF

Note1:.“AbsoluteMaximumRatings”ingRatingsindicateconditionsforwhichthedeviceis

functional,butdonotguaranteespecificperformancelimits.

Note2:Unlessotherwisespecified,testsareperformedatT

j

=

25˚Cwithpulsetestingsothatjunctiontemperaturedoesnotchangeduringtest

Note3:SetcurrentisthecurrentflowingintotheV

+

Basic2-TerminalCurrentSourcecircuitshownonthefirstpageofthisdatasheet.I

SET

isdetermined

bythefollowingformula:I

SET

=

67.7mV/R

SET

(

@

25˚C).Setcurrenterrorisexpressedasapercentdeviationfromthisamount.I

SET

increasesat0.336%/˚C

@

T

j

=

25˚C(227µV/˚C).

Note4:I

SET

isdirectlyproportionaltoabsolutetemperature(˚K).I

SET

atanytemperaturecanbecalculatedfrom:I

SET

=

I

o

(T/T

o

)whereI

o

isI

SET

measuredatT

o

(˚K).

Note5:Forelevatedtemperatureoperation,T

j

maxis:

LM134

LM234

LM334

ThermalResistance

θ

ja

(JunctiontoAmbient)

θ

jc

(JunctiontoCase)

150˚C

125˚C

100˚C

TO-92

180˚C/W(0.4"leads)

160˚C/W(0.125"leads)

N/A32˚C/W80˚C/W

TO-46

440˚C/W

SO-8

165˚C/W

Note6:Humanbodymodel,100pFdischargedthrougha1.5kΩresistor.

2

ElectricalCharacteristics

(Note2)

Parameter

SetCurrentError,V

(Note3)

EquivalentTemperatureError

RatioofSetCurrentto

BiasCurrent

MinimumOperatingVoltage

AverageChangeinSetCurrent

withInputVoltage

TemperatureDependenceof

SetCurrent(Note4)and

EquivalentSlopeError

EffectiveShuntCapacitance15

100µAI

SET

≤1mA

100µA≤I

SET

≤1mA

1.5≤V

+

≤5V

5V≤V

≤30V

100µA≤I

SET

≤1mA0.98T

+

+

=

Conditions

100µA≤I

SET

≤1mA

T

j

=

25˚

100µA≤I

SET

≤1mA

LM134-3,LM234-3

MinTypMax

LM134-6,LM234-6

MinTypMax

Units

%

˚C

2.5V,

±

1

±

3

1418

0.9

0.02

0.01

T

0.05

0.03

1.02T0.97T

261418

0.9

0.02

0.01

T

±

2

±

6

26

V

0.01

0.05

1.03T

%/V

%/V

±

2

15

±

3

%

pF

TypicalPerformanceCharacteristics

OutputImpedance

MaximumSlewRate

LinearOperation

Start-Up

DS005697-30

DS005697-31

DS005697-32

TransientResponseVoltageAcrossR

SET

(V

R

)CurrentNoise

DS005697-33DS005697-34

DS005697-35

TypicalPerformanceCharacteristics

Turn-OnVoltage

(Continued)

RatioofI

SET

toI

BIAS

DS005697-29

DS005697-3

ApplicationHints

TheLM134hasbeendesignedforeaseofapplication,buta

generaldiscussionofdesignfeaturesispresentedhereto

familiarizethedesignerwithdevicecharacteristicswhich

ncludetheeffects

ofslewing,powerdissipation,capacitance,noise,andcon-

tactresistance.

CALCULATINGR

SET

ThetotalcurrentthroughtheLM134(I

SET

)isthesumofthe

currentgoingthroughtheSETresistor(I

R

)andtheLM134’s

biascurrent(I

BIAS

),asshownin

Figure1

.

wherenistheratioofI

SET

toI

BIAS

asspecifiedintheElec-

nistypically18for2µA≤I

SET

≤1mA,theequationcanbe

furthersimplifiedto

formostsetcurrents.

SLEWRATE

Atslewratesaboveagiventhreshold(seecurve),the

wing

rateatwhichthisoccursisdirectlyproportionaltoI

SET

.At

I

SET

=

10µA,maximumdV/dtis0.01V/µs;atI

SET

=

1mA,

thelimitis1V/µtesabovethelimitdonotharmthe

LM134,orcauselargecurrentstoflow.

THERMALEFFECTS

Internalheatingcanhaveasignificanteffectoncurrentregu-

lationforI

SET

greaterthan100µmple,each1Vin-

creaseacrosstheLM134atI

SET

=

1mAwillincreasejunc-

tiontemperatureby≈0.4˚current(I

SET

)

hasatemperaturecoefficientof≈0.33%/˚C,sothechangein

currentduetotemperaturerisewillbe(0.4)(0.33)

=

0.132%.

Thisisa10:1degradationinregulationcomparedtotrue

leffects,therefore,mustbetaken

intoaccountwhenDCregulationiscriticalandI

SET

exceeds

100µnkingoftheTO-46packageortheTO-92

leadscanreducethiseffectbymorethan3:1.

SHUNTCAPACITANCE

Incertainapplications,the15pFshuntcapacitanceofthe

LM134mayhavetobereduced,eitherbecauseofloading

problemsorbecauseitlimitstheACoutputimpedanceofthe

nbeeasilyaccomplishedbybuffering

canreducecapacitancetolessthan3pFandimproveregu-

acteristics

(withtheexceptionofminimuminputvoltage),arenotaf-

fected.

DS005697-27

urrentSource

Agraphshowingtheratioofthesetwocurrentsissupplied

underRatioofI

SET

toI

BIAS

intheTypicalPerformance

rentflowingthroughR

SET

is

determinedbyV

R

,whichisapproximately214µV/˚K(64mV/

298˚K

z

214µV/˚K).

Since(foragivensetcurrent)I

BIAS

issimplyapercentageof

I

SET

,theequationcanberewritten

4

ApplicationHints

NOISE

(Continued)

APPLICATIONASAZEROTEMPERATURE

COEFFICENTCURRENTSOURCE

AddingadiodeandaresistortothestandardLM134con-

figurationcancancelthetemperature-dependentcharacter-

cuitshownin

Figure3

balances

thepositivetempcooftheLM134(about+0.23mV/˚C)with

thenegativetempcoofaforward-biasedsilicondiode(about

−2.5mV/˚C).

CurrentnoisegeneratedbytheLM134isapproximately4

M134isusedas

anactiveloadforatransistoramplifier,inputreferrednoise

cases,thisisac-

ceptableandasinglestageamplifiercanbebuiltwithavolt-

agegainexceeding2000.

LEADRESISTANCE

Thesensevoltagewhichdeterminesoperatingcurrentofthe

level,thermocoupleor

leadresistanceeffectsshouldbeminimizedbylocatingthe

-

sonly0.7Ωcontact

resistancetoreduceoutputcurrentby1%atthe1mAlevel.

SENSINGTEMPERATURE

TheLM134makesanidealremotetemperaturesensorbe-

causeitscurrentmodeoperationdoesnotloseaccuracy

currentisdirectlyproportionalto

absolutetemperatureindegreesKelvin,accordingtothefol-

lowingformula:

CalibrationoftheLM134isgreatlysimplifiedbecauseofthe

factthatmostoftheinitialinaccuracyisduetoagainterm

(slopeerror)ansthatacalibration

consistingofagainadjustmentonlywilltrimbothslopeand

tion,gainadjustmentisaone

pointtrimbecausetheoutputoftheLM134extrapolatesto

zeroat0˚K,independentofR

SET

oranyinitialinaccuracy.

DS005697-28

mpcoCurrentSource

Thesetcurrent(I

SET

)isthesumofI

1

andI

2

,eachcontribut-

ingapproximately50%ofthesetcurrent,andI

BIAS

.I

BIAS

is

usuallyincludedintheI

1

termbyincreasingtheV

R

value

usedforcalculationsby5.9%.(SeeCALCULATINGR

SET

.)

Thefirststepistominimizethetempcoofthecircuit,using

pleisgivenusingavalueof

+227µV/˚CasthetempcooftheLM134(whichincludesthe

I

BIAS

component),and−2.5mV/˚Casthetempcoofthedi-

ode(forbestresults,thisvalueshouldbedirectlymeasured

orobtainedfromthemanufacturerofthediode).

DS005697-4

justment

ThispropertyoftheLM134isillustratedintheaccompanying

a'b'c'rimdoneatT2willmove

theoutputfrombtob'andwillsimultaneouslycorrectthe

gaintrimcanbedoneonR

SET

orontheloadresistorused

rroraftertrimwillnormally

belessthan

±

1%.Tomaintainthisaccuracy,however,alow

temperaturecoefficientresistormustbeusedforR

SET

.

A33ppm/˚CdriftofR

SET

willgivea1%slopeerrorbecause

theresistorwillnormallyseeaboutthesametemperature

tingR

SET

fromtheLM134

requires3wiresandhasleadresistanceproblems,soisnot

ilmresistorswithlessthan

20ppm/˚undresistors

mayalsobeusedwherebeststabilityisrequired.

5

WiththeR

1

toR

2

ratiodetermined,valuesforR

1

andR

2

formulaforcalculatingthesetcurrentatT

=

25˚Cisshown

below,followedbyanexamplethatassumestheforward

voltagedropacrossthediode(V

D

)is0.6V,thevoltage

acrossR

1

is67.7mV(64mV+5.9%toaccountforI

BIAS

),

andR

2

/R

1

=

10(fromthepreviouscalculations).

ApplicationHints

(Continued)

Iftheestimateforthetempcoofthediode’sforwardvoltage

dropwasoff,thetempcocancellationisstillreasonablyef-

thetempcoofthediodeis2.6mV/˚Cinstead

of2.5mV/˚C(anerrorof4%).Thetempcoofthecircuitis

now:

ThiscircuitwilleliminatemostoftheLM134’stemperature

coefficient,anditdoesagoodjobeveniftheestimatesofthe

diode’scharacteristicsarenotaccurate(asthefollowingex-

amplewillshow).Forlowesttempcowithaspecificdiodeat

thedesiredI

SET

,however,thecircuitshouldbebuiltand

easuredtempcoofI

SET

is

positive,R

2

esultingtempcois

negative,R

2

ommendeddiode

foruseinthiscircuitisthe1N457becauseitstempcoiscen-

teredat11timesthetempcooftheLM134,allowingR

2

=

10

R

1

.Youcanalsousethiscircuittocreateacurrentsource

withnon-zerotempcosbysettingthetempcocomponentof

thetempcoequationtothedesiredvalueinsteadof0.

EXAMPLE:A1mA,Zero-TempcoCurrentSource

First,solveforR

1

andR

2

:

A1mALM134currentsourcewithnotemperaturecompen-

sationwouldhaveasetresistorof68Ωandaresulting

tempcoof

Soevenifthediode’stempcovariesasmuchas

±

4%from

itsestimatedvalue,thecircuitstilleliminates98%ofthe

LM134’sinherenttempco.

TypicalApplications

GroundReferredFahrenheitThermometer

ThevaluesofR

1

andR

2

canbechangedtostandard1%re-

sistorvalues(R

1

=

133ΩandR

2

=

1.33kΩ)withlessthana

0.75%error.

Iftheforwardvoltagedropofthediodewas0.65Vinsteadof

theestimateof0.6V(anerrorof8%),theactualsetcurrent

willbe

DS005697-15

*

SelectR3

=

V

REF

/583µA.V

REF

maybeanystablepositivevoltage≥2V

TrimR3tocalibrate

anerroroflessthan5%.

6

Applications

(Continued)

TerminatingRemoteSensorforVoltageOutput

DS005697-14

LowOutputImpedanceThermometer

DS005697-6

*OutputimpedanceoftheLM134atthe“R”pinisapproximately

Typical

TypicalApplications

(Continued)

LowInputVoltageReferenceDriver

MicropowerBias

DS005697-17

DS005697-18

RampGenerator

DS005697-19

8

TypicalApplications

(Continued)

1.2VRegulatorwith1.8VMinimumInput

1.2VReferenceOperateson10µAand2V

DS005697-20

*SelectratioofR1toR2toobtainzerotemperaturedrift

DS005697-7

*SelectratioofR1toR2forzerotemperaturedrift

ZenerBiasing

AlternateTrimmingTechnique

BufferforPhotoconductiveCell

DS005697-51

DS005697-49

DS005697-50

*For

±

10%adjustment,selectR

SET

10%high,andmakeR1≈3R

SET

FETCascodingforLowCapacitanceand/orUltraHighOutputImpedance

DS005697-21

*SelectQ1orQ2toensureatleast1VacrosstheLM134.V

p

(1−

I

SET

/I

DSS

)≥1.2V.

DS005697-22

TypicalApplications

(Continued)

In-LineCurrentLimiterGeneratingNegativeOutputImpedance

DS005697-23

*Z

OUT

≈−16

•

R1(R1/V

IN

mustnotexceedI

SET

)

DS005697-9

*

minimizesinrushcurrenttoadirectshort.

SchematicDiagram

DS005697-11

10

11

PhysicalDimensions

inches(millimeters)unlessotherwisenoted

OrderNumberLM134H,LM134H-3,

LM134H-6,LM234HorLM334H

NSPackageNumberH03H

12

PhysicalDimensions

inches(millimeters)unlessotherwisenoted(Continued)

SOPackage(M)

OrderNumberLM334MorLM334SM

NSPackageNumberM08A

OrderNumberLM334Z,LM234Z-3orLM234Z-6

NSPackageNumberZ03A

L

M

1

3

4

/

L

M

2

3

4

/

L

M

3

3

4

3

-

T

e

r

m

i

n

a

l

A

d

j

u

s

t

a

b

l

e

C

u

r

r

e

n

t

S

o

u

r

c

e

s

LIFESUPPORTPOLICY

NATIONAL’SPRODUCTSARENOTAUTHORIZEDFORUSEASCRITICALCOMPONENTSINLIFESUPPORTDE-

VICESORSYSTEMSWITHOUTTHEEXPRESSWRITTENAPPROVALOFTHEPRESIDENTOFNATIONALSEMI-

herein:

calcomponentisanycomponentofalifesupport

pportdevicesorsystemsaredevicesorsys-

deviceorsystemwhosefailuretoperformcanberea-

temswhich,(a)areintendedforsurgicalimplantinto

sonablyexpectedtocausethefailureofthelifesupport

thebody,or(b)supportorsustainlife,andwhosefail-

deviceorsystem,ortoaffectitssafetyoreffectiveness.

uretoperformwhenproperlyusedinaccordance

withinstructionsforuseprovidedinthelabeling,can

bereasonablyexpectedtoresultinasignificantinjury

totheuser.

NationalSemiconductor

Corporation

Americas

Tel:1-800-272-9959

Fax:1-800-737-7018

Email:support@

NationalSemiconductor

Europe

Fax:+49(0)180-5308586

Email:t@

DeutschTel:+49(0)180-5308585

EnglishTel:+49(0)180-5327832

FrançaisTel:+49(0)180-5329358

ItalianoTel:+49(0)180-5341680

NationalSemiconductor

AsiaPacificCustomer

ResponseGroup

Tel:65-2544466

Fax:65-2504466

Email:t@

NationalSemiconductor

JapanLtd.

Tel:81-3-5639-7560

Fax:81-3-5639-7507

Nationaldoesnotassumeanyresponsibilityforuseofanycircuitrydescribed,nocircuitpatentlicensesareimpliedandNationalreservestherightatanytimewithoutnoticetochangesaidcircuitryandspecifications.