LM386

LM386

LowVoltageAudioPowerAmplifier

GeneralDescription

TheLM386isapoweramplifierdesignedforuseinlowvolt-ageconsumerapplications.Thegainisinternallysetto20tokeepexternalpartcountlow,buttheadditionofanexternalresistorandcapacitorbetweenpins1and8willincreasethegaintoanyvaluefrom20to200.

Theinputsaregroundreferencedwhiletheoutputautomati-callybiasestoone-halfthesupplyvoltage.Thequiescentpowerdrainisonly24milliwattswhenoperatingfroma6voltsupply,makingtheLM386idealforbatteryoperation.

Features

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Batteryoperation

Minimumexternalparts

Widesupplyvoltagerange:4V–12Vor5V–18VLowquiescentcurrentdrain:4mAVoltagegainsfrom20to200Groundreferencedinput

Self-centeringoutputquiescentvoltage

Lowdistortion:0.2%(AV=20,VS=6V,RL=8Ω,PO=125mW,f=1kHz)

nAvailablein8pinMSOPpackage

Applications

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AM-FMradioamplifiers

PortabletapeplayeramplifiersIntercoms

TVsoundsystemsLinedrivers

UltrasonicdriversSmallservodriversPowerconverters

EquivalentSchematicandConnectionDiagrams

SmallOutline,

MoldedMiniSmallOutline,andDual-In-LinePackages

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TopView

OrderNumberLM386M-1,LM386MM-1,LM386N-1,LM386N-3orLM386N-4SeeNSPackageNumberM08A,MUA08AorN08E

©2000NationalSemiconductorCorporationDS006976www.national.com

LM386AbsoluteMaximumRatings(Note2)

IfMilitary/Aerospacespecifieddevicesarerequired,pleasecontacttheNationalSemiconductorSalesOffice/Distributorsforavailabilityandspecifications.SupplyVoltage

(LM386N-1,-3,LM386M-1)SupplyVoltage(LM386N-4)PackageDissipation(Note3)(LM386N)(LM386M)(LM386MM-1)InputVoltage

StorageTemperatureOperatingTemperatureJunctionTemperatureSolderingInformation

15V22V

1.25W0.73W0.595W±0.4V

−65˚Cto+150˚C

0˚Cto+70˚C

+150˚C

Dual-In-LinePackageSoldering(10sec)+260˚CSmallOutlinePackage(SOICandMSOP)VaporPhase(60sec)+215˚CInfrared(15sec)+220˚CSeeAN-450“SurfaceMountingMethodsandTheirEffectonProductReliability”forothermethodsofsolderingsurfacemountdevices.ThermalResistance

37˚C/WθJC(DIP)

107˚C/WθJA(DIP)

35˚C/WθJC(SOPackage)

172˚C/WθJA(SOPackage)

210˚C/WθJA(MSOP)

56˚C/WθJC(MSOP)

ElectricalCharacteristics(Notes1,2)

TA=25˚C

Parameter

OperatingSupplyVoltage(VS)

LM386N-1,-3,LM386M-1,LM386MM-1LM386N-4

QuiescentCurrent(IQ)OutputPower(POUT)

LM386N-1,LM386M-1,LM386MM-1LM386N-3LM386N-4VoltageGain(AV)Bandwidth(BW)

TotalHarmonicDistortion(THD)PowerSupplyRejectionRatio(PSRR)InputResistance(RIN)InputBiasCurrent(IBIAS)

VS=6V,Pins2and3Open

Note1:Allvoltagesaremeasuredwithrespecttothegroundpin,unlessotherwisespecified.

Note2:AbsoluteMaximumRatingsindicatelimitsbeyondwhichdamagetothedevicemayoccur.OperatingRatingsindicateconditionsforwhichthedeviceisfunc-tional,butdonotguaranteespecificperformancelimits.ElectricalCharacteristicsstateDCandACelectricalspecificationsunderparticulartestconditionswhichguar-anteespecificperformancelimits.ThisassumesthatthedeviceiswithintheOperatingRatings.Specificationsarenotguaranteedforparameterswherenolimitis

given,however,thetypicalvalueisagoodindicationofdeviceperformance.

Note3:Foroperationinambienttemperaturesabove25˚C,thedevicemustbederatedbasedona150˚Cmaximumjunctiontemperatureand1)athermalresis-tanceof107˚C/Wjunctiontoambientforthedual-in-linepackageand2)athermalresistanceof170˚C/Wforthesmalloutlinepackage.

ConditionsMin45

TypMax1218

UnitsVVmAmWmWmWdBdBkHz%dBkΩnA

VS=6V,VIN=0

VS=6V,RL=8Ω,THD=10%VS=9V,RL=8Ω,THD=10%VS=16V,RL=32Ω,THD=10%VS=6V,f=1kHz10µFfromPin1to8VS=6V,Pins1and8OpenVS=6V,RL=8Ω,POUT=125mWf=1kHz,Pins1and8OpenVS=6V,f=1kHz,CBYPASS=10µFPins1and8Open,ReferredtoOutput

250500700

43257001000263000.25050250

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LM386ApplicationHints

GAINCONTROL

TomaketheLM386amoreversatileamplifier,twopins(1and8)areprovidedforgaincontrol.Withpins1and8openthe1.35kΩresistorsetsthegainat20(26dB).Ifacapacitorisputfrompin1to8,bypassingthe1.35kΩresistor,thegainwillgoupto200(46dB).Ifaresistorisplacedinserieswiththecapacitor,thegaincanbesettoanyvaluefrom20to200.Gaincontrolcanalsobedonebycapacitivelycou-plingaresistor(orFET)frompin1toground.

Additionalexternalcomponentscanbeplacedinparallelwiththeinternalfeedbackresistorstotailorthegainandfre-quencyresponseforindividualapplications.Forexample,wecancompensatepoorspeakerbassresponsebyfre-quencyshapingthefeedbackpath.ThisisdonewithaseriesRCfrompin1to5(parallelingtheinternal15kΩresistor).For6dBeffectivebassboost:R.15kΩ,thelowestvalueforgoodstableoperationisR=10kΩifpin8isopen.Ifpins1and8arebypassedthenRaslowas2kΩcanbeused.Thisrestrictionisbecausetheamplifierisonlycompensatedforclosed-loopgainsgreaterthan9.

INPUTBIASING

Theschematicshowsthatbothinputsarebiasedtogroundwitha50kΩresistor.Thebasecurrentoftheinputtransis-torsisabout250nA,sotheinputsareatabout12.5mVwhenleftopen.IfthedcsourceresistancedrivingtheLM386ishigherthan250kΩitwillcontributeverylittleadditionaloffset(about2.5mVattheinput,50mVattheoutput).Ifthedcsourceresistanceislessthan10kΩ,thenshortingtheunusedinputtogroundwillkeeptheoffsetlow(about2.5mVattheinput,50mVattheoutput).Fordcsourceresistancesbetweenthesevalueswecaneliminateexcessoffsetbyput-tingaresistorfromtheunusedinputtoground,equalinvaluetothedcsourceresistance.Ofcoursealloffsetprob-lemsareeliminatediftheinputiscapacitivelycoupled.

WhenusingtheLM386withhighergains(bypassingthe1.35kΩresistorbetweenpins1and8)itisnecessarytoby-passtheunusedinput,preventingdegradationofgainandpossibleinstabilities.Thisisdonewitha0.1µFcapacitororashorttogrounddependingonthedcsourceresistanceonthedriveninput.

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LM386TypicalPerformanceCharacteristics

QuiescentSupplyCurrentvsSupplyVoltage

PowerSupplyRejectionRatio(ReferredtotheOutput)vsFrequency

Peak-to-PeakOutputVoltageSwingvsSupplyVoltage

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VoltageGainvsFrequencyDistortionvsFrequencyDistortionvsOutputPower

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DeviceDissipationvsOutputPower—4ΩLoadDeviceDissipationvsOutputPower—8ΩLoad

DeviceDissipationvsOutputPower—16ΩLoad

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DS006976-18

DS006976-19

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LM386TypicalApplications

AmplifierwithGain=20

MinimumParts

AmplifierwithGain=200

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AmplifierwithGain=50LowDistortionPowerWienbridgeOscillator

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AmplifierwithBassBoostSquareWaveOscillator

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LM386TypicalApplications

(Continued)

FrequencyResponsewithBassBoost

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AMRadioPowerAmplifier

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Note4:TwistSupplyleadandsupplygroundverytightly.Note5:Twistspeakerleadandgroundverytightly.

Note6:FerritebeadinFerroxcubeK5-001-001/3Bwith3turnsofwire.Note7:R1C1bandlimitsinputsignals.

Note8:AllcomponentsmustbespacedverycloselytoIC.

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LM386PhysicalDimensions

inches(millimeters)unlessotherwisenoted

SOPackage(M)

OrderNumberLM386M-1NSPackageNumberM08A

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LM386PhysicalDimensions

inches(millimeters)unlessotherwisenoted(Continued)

8-Lead(0.118”Wide)MoldedMiniSmallOutlinePackage

OrderNumberLM386MM-1NSPackageNumberMUA08A

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LM386LowVoltageAudioPowerAmplifierPhysicalDimensions

inches(millimeters)unlessotherwisenoted(Continued)

Dual-In-LinePackage(N)

OrderNumberLM386N-1,LM386N-3orLM386N-4

NSPackageNumberN08E

LIFESUPPORTPOLICY

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

NationalSemiconductorCorporationAmericas

Tel:1-800-272-9959Fax:1-800-737-7018Email:support@nsc.com

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Fax:+49(0)180-5308586Email:europe.support@nsc.com

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

2.Acriticalcomponentisanycomponentofalifesupportdeviceorsystemwhosefailuretoperformcanbereasonablyexpectedtocausethefailureofthelifesupportdeviceorsystem,ortoaffectitssafetyoreffectiveness.

NationalSemiconductorAsiaPacificCustomerResponseGroupTel:65-2544466Fax:65-2504466

Email:ap.support@nsc.com

NationalSemiconductorJapanLtd.

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

Nationaldoesnotassumeanyresponsibilityforuseofanycircuitrydescribed,nocircuitpatentlicensesareimpliedandNationalreservestherightatanytimewithoutnoticetochangesaidcircuitryandspecifications.