Texas Instruments LM317A Handleiding

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AnIMPORTANTNOTICEattheendofthisdatasheetaddressesavailability,warranty,changes,useinsafety-criticalapplications,

intellectualpropertymattersandotherimportantdisclaimers.PRODUCTIONDATA.

LM317A

SNVSAC2A–MARCH2015–REVISEDJUNE2020

LM317A1%Accurate1.5AAdjustableVoltageRegulator

1

1Features

1

•Foranewerdrop-inalternative,seetheLM317

•Typical0.005%/Vlineregulation

•1%outputvoltagetolerance

•1.5-Aoutputcurrent

•Adjustableoutputdownto1.25V

•Input-outputdifferentialupto40V

•Currentlimitconstantwithtemperature

•Nooutputcapacitorrequired

•Short-circuitprotectedoutput

•−40°Cto125°Coperatingtemperaturerange

2Applications

•AutomotiveLEDlighting

•Batterychargers

•Postregulationforswitchingsupplies

•Constant-currentregulator

•Microprocessorsupplies

TypicalApplication

*Neededifdeviceismorethan6inchesfromfilter

capacitors.

†Optional—improvestransientresponse

††

3Description

TheLM317Aadjustable3-terminal,positive-voltage

regulatorsarecapableofsupplyingcurrentinexcess

of1.5Aovera1.25-Vto37-Voutputrangeand

provide1%output-voltageaccuracy.Bothline

regulationandloadregulationarebetterachieved

withtheLM317Adevicethanwithstandardfixed

regulators.

TheLM317Aoffersfulloverloadprotectionsuchas

overcurrent,thermal-overloadprotection,andsafe-

areaprotection.Alloverloadprotectioncircuitry

remainsfullyfunctionaleveniftheadjustment

terminalisdisconnected.

Typically,nocapacitorsareneededunlessthedevice

issituatedmorethan6inchesfromtheinputfilter

capacitors,inwhichcaseaninputbypassisneeded.

Anoptionaloutputcapacitorcanbeaddedtoimprove

transientresponseandcanbereplacedwitha

ceramicandappropriateESR.Theadjustment

terminalcanbebypassedtoachieveveryhighripple-

rejectionratiosthataredifficulttoachievewith

standard3-terminalregulators.

BecausetheLM317Aregulatorisfloatinganddetects

onlytheinput-to-outputdifferentialvoltage,supplies

ofseveralhundredvoltscanberegulatedaslongas

themaximuminput-to-outputdifferentialisnot

exceeded.Exceedingthemaximuminput-to-output

deferentialwillresultinshort-circuitingtheoutput.By

connectingafixedresistorbetweentheadjustment

pinandoutput,theLM317Acanbealsousedasa

precisioncurrentregulator.

Forapplicationsrequiringgreateroutputcurrent,see

theLM150series(3A)andLM138series(5A)data

sheets.Forthenegativecomplement,seetheLM137

seriesdatasheet.

DeviceInformation

(1)

PART

NUMBER

PACKAGEBODYSIZE(NOM)

LM317A

TO-220(3)14.986mm×10.16mm

SOT-223(4)6.50mm×3.50mm

TO(3)8.255mm×8.255mm

TO-252(3)6.58mm×6.10mm

(1)Forallavailablepackages,seetheorderableaddendumat

theendofthedatasheet.

Product specificaties