2024年5月10日发(作者：tcl j630t)

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LM138/LM338

5-Amp

Adjustable

Regulators

May1998

LM138/LM338

5-AmpAdjustableRegulators

GeneralDescription

TheLM138seriesofadjustable3-terminalpositivevoltage

regulatorsiscapableofsupplyinginexcessof5Aovera

eexceptionallyeasyto

useandrequireonly2resistorstosettheoutputvoltage.

Carefulcircuitdesignhasresultedinoutstandingloadand

lineregulation—comparabletomanycommercialpower

138familyissuppliedinastandard3-lead

transistorpackage.

AuniquefeatureoftheLM138familyistime-dependentcur-

rentlimitcircuitryallowspeakcurrents

ofupto12Atobedrawnfromtheregulatorforshortperiods

lowstheLM138tobeusedwithheavytran-

sientloadsandspeedsstart-upunderfull-loadconditions.

Undersustainedloadingconditions,thecurrentlimitde-

-

cludedonthechiparethermaloverloadprotectionandsafe

adprotection

remainsfunctionaleveniftheadjustmentpinisaccidentally

disconnected.

Normally,nocapacitorsareneededunlessthedeviceissitu-

atedmorethan6inchesfromtheinputfiltercapacitorsin

utcapacitor

canbeaddedtoimprovetransientresponse,whilebypass-

ingtheadjustmentpinwillincreasetheregulator’sripplere-

jection.

Besidesreplacingfixedregulatorsordiscretedesigns,the

theregulatoris“floating”andseesonlytheinput-to-output

differentialvoltage,suppliesofseveralhundredvoltscanbe

regulatedaslongasthemaximuminputtooutputdifferential

,donotshort-circuitoutputtoground.

ThepartnumbersintheLM138serieswhichhaveaKsuffix

arepackagedinastandardSteelTO-3package,whilethose

withaTsuffixarepackagedinaTO-220plasticpackage.

TheLM138isratedfor−55˚C≤T

J

≤+150˚C,andtheLM338

isratedfor0˚C≤T

J

≤+125˚C.

Features

n

n

n

n

n

n

n

Guaranteed7Apeakoutputcurrent

Guaranteed5Aoutputcurrent

Adjustableoutputdownto1.2V

Guaranteedthermalregulation

Currentlimitconstantwithtemperature

P

+

ProductEnhancementtested

Outputisshort-circuitprotected

Applications

nAdjustablepowersupplies

nConstantcurrentregulators

nBatterychargers

ConnectionDiagrams

(SeePhysicalDimensionsectionforfurtherinformation)

(TO-220)

PlasticPackage

(TO-3STEEL)

MetalCanPackage

DS009060-31

DS009060-30

FrontView

OrderNumberLM338T

SeeNSPackageNumberT03B

BottomView

OrderNumberLM138KSTEELorLM338KSTEEL

SeeNSPackageNumberK02A

©

AbsoluteMaximumRatings

(Note1)

IfMilitary/Aerospacespecifieddevicesarerequired,

pleasecontacttheNationalSemiconductorSalesOffice/

Distributorsforavailabilityandspecifications.

(Note4)

PowerDissipation

Input/OutputVoltageDifferential

StorageTemperature

Internallylimited

+40V,−0.3V

−65˚Cto+150˚C

LeadTemperature

MetalPackage(Soldering,10seconds)

PlasticPackage(Soldering,4seconds)

ESDTolerance

300˚C

260˚C

TBD

OperatingTemperatureRange

LM138

LM338

−55˚C≤T

J

≤+150˚C

0˚C≤T

J

≤+125˚C

ElectricalCharacteristics

SpecificationswithstandardtypefaceareforT

J

=

25˚C,andthosewithboldfacetypeapplyoverfullOperatingTempera-

otherwisespecified,V

IN

−V

OUT

=

5V;andI

OUT

=

10mA.(Note2)

Symbol

V

REF

V

RLINE

V

RLOAD

Parameter

ReferenceVoltage

LineRegulation

LoadRegulation

ThermalRegulation

I

ADJ

∆I

ADJ

∆V

R/T

I

LOAD

(Min)

I

CL

AdjustmentPinCurrent

AdjustmentPinCurrentChange

TemperatureStability

MinimumLoadCurrent

CurrentLimit

10mA≤I

OUT

≤5A,

3V≤(V

IN

−V

OUT

)≤35V

T

MIN

≤T

J

≤T

MAX

V

IN

−V

OUT

=

35V

V

IN

−V

OUT

≤10V

DC

0.5msPeak

V

IN

−V

OUT

=

30V

V

N

RMSOutputNoise,

%

ofV

OUT

10Hz≤f≤10kHz

5

7

8

12

1

0.003

1

A

A

A

%

1

3.55

%

mA

Conditions

Min

3V≤(V

IN

−V

OUT

)≤35V,

10mA≤I

OUT

≤5A,P≤50W

3V≤(V

IN

−V

OUT

)≤35V(Note3)

10mA≤I

OUT

≤5A(Note3)

20msPulse

0.005

0.02

0.1

0.3

0.002

45

0.2

0.01

0.04

0.3

0.6

0.01

100

5

%/V

%/V

%

%

%/W

µA

µA

1.19

LM138

Typ

1.24

Max

1.29V

Units