LM3876 Overture Audio Power Amp Series High-Perf 56W Audio Pwr Amp w/Mute

29 Pages·2015·0.91 MB·English

LM3876
www.ti.com SNAS090D–APRIL1995–REVISEDMARCH2013
LM3876 Overture™ Audio Power Amplifier Series
High-Performance 56W Audio Power Amplifier w/Mute
CheckforSamples:LM3876
FEATURES DESCRIPTION
1
• 56WContinuousAverageOutputPowerinto The LM3876 is a high-performance audio power
23 amplifier capable of delivering 56W of continuous
8Ω
average power to an 8Ω load with 0.1% THD+N from
• 100WInstantaneousPeakOutputPower
20Hz–20kHz.
Capability
The performance of the LM3876, utilizing its Self
• Signal-to-Noise Ratio≥ 95dB(Min)
Peak Instantaneous Temperature (°Ke) (SPiKe)
• AnInputMuteFunction protection circuitry, puts it in a class above discrete
• Output ProtectionfromaShorttoGroundor and hybrid amplifiers by providing an inherently,
totheSuppliesViaInternalCurrentLimiting dynamically protected Safe Operating Area (SOA).
SPiKe protection means that these parts are
Circuitry
completely safeguarded at the output against
• Output Over-VoltageProtectionagainst
overvoltage, undervoltage, overloads,including shorts
TransientsfromInductiveLoads
to the supplies, thermal runaway, and instantaneous
• SupplyUnder-VoltageProtection,notAllowing temperaturepeaks.
InternalBiasingtoOccur when|V |+|V |≤
EE CC The LM3876 maintains an excellent signal-to-noise
12V,thusEliminatingTurn-Onand Turn-Off
ratio of greater than 95dB (min) with a typical low
Transients noise floor of 2.0μV. It exhibits extremely low THD+N
• 11-LeadTO-220Package values of 0.06% at the rated output into the rated
load over the audio spectrum, and provides excellent
• WideSupply Range20V-94V
linearity with an IMD (SMPTE) typical rating of
0.004%.
APPLICATIONS
• ComponentStereo
• CompactStereo
• Self-PoweredSpeakers
• Surround-SoundAmplifiers
• High-EndStereoTVs
1
Pleasebeawarethatanimportantnoticeconcerningavailability,standardwarranty,anduseincriticalapplicationsof
TexasInstrumentssemiconductorproductsanddisclaimerstheretoappearsattheendofthisdatasheet.
Overtureisatrademarkofdcl_owner.
2
Allothertrademarksarethepropertyoftheirrespectiveowners.
3
PRODUCTIONDATAinformationiscurrentasofpublicationdate. Copyright©1995–2013,TexasInstrumentsIncorporated
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarilyincludetestingofallparameters.
LM3876
SNAS090D–APRIL1995–REVISEDMARCH2013 www.ti.com
Typical Application
*Optionalcomponentsdependentuponspecificdesignrequirements.RefertoExternalComponentsDescriptionfora
componentfunctionaldescription.
Figure1. TypicalAudioAmplifierApplicationCircuit
Connection Diagram
TopView
†ConnectPin5toV+forCompatibilitywithLM3886.
Figure2. TO-220andPFM PlasticPackages
SeePackageNumbersNDJ0011BandNDA0011B(1)
(1) TheLM3876TpackageTA11Bisanon-isolatedpackage,settingthetabofthedeviceandtheheatsinkatV−potentialwhenthe
LM3876isdirectlymountedtotheheatsinkusingonlythermalcompound.Ifamicawasherisusedinadditiontothermalcompound,
θ (casetosink)isincreased,buttheheatsinkwillbeisolatedfromV−.
CS
2 SubmitDocumentationFeedback Copyright©1995–2013,TexasInstrumentsIncorporated
ProductFolderLinks:LM3876
LM3876
www.ti.com SNAS090D–APRIL1995–REVISEDMARCH2013
Thesedeviceshavelimitedbuilt-inESDprotection.Theleadsshouldbeshortedtogetherorthedeviceplacedinconductivefoam
duringstorageorhandlingtopreventelectrostaticdamagetotheMOSgates.
Absolute Maximum Ratings (1)(2)(3)
SupplyVoltage|V+|+|V−|(NoSignal) 94V
SupplyVoltage|V+|+|V−|(InputSignal) 84V
CommonModeInputVoltage (V+orV−)and
|V+|+|V−|≤80V
DifferentialInputVoltage 60V
OutputCurrent InternallyLimited
PowerDissipation (4) 125W
ESDSusceptibility (5) 3000V
JunctionTemperature (6) 150°C
SolderingInformation TPackage(10seconds) 260°C
StorageTemperature −40°Cto+150°C
ThermalResistance θ 1°C/W
JC
θ 43°C/W
JA
(1) AbsoluteMaximumRatings indicatelimitsbeyondwhichdamagetothedevicemayoccur.OperatingRatings indicateconditionsfor
whichthedeviceisfunctional.ElectricalCharacteristicsstateDCandACelectricalspecificationsunderparticulartestconditionsand
specificperformancelimits.ThisassumesthatthedeviceiswithintheOperatingRatings.Thetypicalvalueisagoodindicationof
deviceperformance.
(2) AllvoltagesaremeasuredwithrespecttotheGNDpin(pin7),unlessotherwisespecified.
(3) IfMilitary/Aerospacespecifieddevicesarerequired,pleasecontacttheTexasInstrumentsSalesOffice/Distributorsforavailabilityand
specifications.
(4) Foroperatingatcasetemperaturesabove25°C,thedevicemustbederatedbasedona150°Cmaximumjunctiontemperatureanda
thermalresistanceofθ =1.0°C/W(junctiontocase).RefertoFigure38inApplicationInformationunderTHERMAL
JC
CONSIDERATIONS.
(5) Humanbodymodel,100pFdischargedthrougha1.5kΩresistor.
(6) Theoperatingjunctiontemperaturemaximumis150°C,however,theinstantaneousSafeOperatingAreatemperatureis250°C.
Operating Ratings (1)(2)(3)
TemperatureRange T ≤T ≤T −20°C≤T ≤+85°C
MIN A MAX A
SupplyVoltage|V+|+|V−| 24Vto84V
(1) AllvoltagesaremeasuredwithrespecttotheGNDpin(pin7),unlessotherwisespecified.
(2) AbsoluteMaximumRatings indicatelimitsbeyondwhichdamagetothedevicemayoccur.OperatingRatings indicateconditionsfor
whichthedeviceisfunctional.ElectricalCharacteristicsstateDCandACelectricalspecificationsunderparticulartestconditionsand
specificperformancelimits.ThisassumesthatthedeviceiswithintheOperatingRatings.Thetypicalvalueisagoodindicationof
deviceperformance.
(3) Operationisspecifiedupto84V,however,distortionmaybeintroducedfromSPiKeProtectionCircuitrywhenoperatingabove70Vif
properthermalconsiderationsarenottakenintoaccount.RefertotheTHERMALCONSIDERATIONSformoreinformation.(See
Figure5)
Copyright©1995–2013,TexasInstrumentsIncorporated SubmitDocumentationFeedback 3
ProductFolderLinks:LM3876
LM3876
SNAS090D–APRIL1995–REVISEDMARCH2013 www.ti.com
Electrical Characteristics (1)(2)
ThefollowingspecificationsapplyforV+=+35V,V−=−35V,I =−0.5mAwithR =8Ωunlessotherwisespecified.Limits
MUTE L
applyforT =25°C.
A
LM3876 Units
Parameter TestConditions
Typical(3) Limit(4) (Limits)
|V+|+|V−| PowerSupplyVoltage (5) V −V−≥9V 18 24 V(min)
pin7
84 V(max)
A MuteAttenuation Pin8Openorat0V,Mute:On
M
CurrentoutofPin8>0.5mA, 120 80 dB(min)
Mute:Off
P (6) OutputPower(ContinuousAverage) THD+N=0.1%(max) 56 40 W(min)
O
f=1kHz;f=20kHz
PeakP InstantaneousPeakOutputPower 100 W
O
THD+N TotalHarmonicDistortionPlusNoise 40W,20Hz≤f≤20kHz 0.06 %
A =26dB
V
SR (6) SlewRate (7) V =1.2Vrms,f=10kHz, 11 5 V/μs(min)
IN
Square-Wave,R =2kΩ
L
I+(8) TotalQuiescentPowerSupplyCurrent V =0V,V =0V,I =0A,I =0A 30 70 mA(max)
CM o o mute
V (8) InputOffsetVoltage V =0V,I =0mA 1 15 mV(max)
OS CM o
I InputBiasCurrent V =0V,I =0mA 0.2 1 μA(max)
B CM o
I InputOffsetCurrent V =0V,I =0mA 0.01 0.2 μA(max)
OS CM o
I OutputCurrentLimit |V+|=|V−|=12V,t =10ms,V =0V 6 4 A(min)
o ON O
V (8) OutputDropoutVoltage (9) |V+–V |,V+=20V,I =+100mA 1.6 5 V(max)
od O o
|V –V−|,V−=−20V,I =−100mA 2.7 5 V(max)
O o
PSRR (8) PowerSupplyRejectionRatio V+=40Vto20V,V−=−40V, 120 85 dB(min)
V =0V,I =0mA
CM o
V+=40V,V−=−40Vto−20V, 120 85 dB(min)
V =0V,I =0mA
CM o
CMRR (8) CommonModeRejectionRatio V+=60Vto20V,V−=−20Vto−60V, 120 80 dB(min)
V =20Vto−20V,I =0mA
CM o
A (8) OpenLoopVoltageGain |V+|=|V−|=40V,R =2kΩ,ΔV =60V 120 90 dB(min)
VOL L O
GBWP Gain-BandwidthProduct |V+|=|V−|=40V 8 2 MHz(min)
f =100kHz,V =50mVrms
O IN
e (6) InputNoise IHF—AWeightingFilter 2.0 8 μV(max)
IN
R =600Ω(InputReferred)
IN
SNR Signal-to-NoiseRatio P =1W,A-Weighted, 98 dB
O
Measuredat1kHz,R =25Ω
S
P =40W,A-Weighted, 114 dB
O
Measuredat1kHz,R =25Ω
S
(1) AllvoltagesaremeasuredwithrespecttotheGNDpin(pin7),unlessotherwisespecified.
(2) AbsoluteMaximumRatings indicatelimitsbeyondwhichdamagetothedevicemayoccur.OperatingRatings indicateconditionsfor
whichthedeviceisfunctional.ElectricalCharacteristicsstateDCandACelectricalspecificationsunderparticulartestconditionsand
specificperformancelimits.ThisassumesthatthedeviceiswithintheOperatingRatings.Thetypicalvalueisagoodindicationof
deviceperformance.
(3) Typicalsaremeasuredat25°Candrepresenttheparametricnorm.
(4) LimitsarespecifiedtoTI'sAOQL(AverageOutgoingQualityLevel).
(5) V−musthaveatleast−9Vatitspinwithreferencetogroundinorderfortheunder-voltageprotectioncircuitrytobedisabled.
(6) ACElectricalTest;refertoTestCircuit#2(ACElectricalTestCircuit).
(7) Thefeedbackcompensationnetworklimitsthebandwidthoftheclosed-loopresponseandsotheslewratewillbereducedduetothe
highfrequencyroll-off.Withoutfeedbackcompensation,theslewrateistypically16V/μs.
(8) DCElectricalTest;refertoTestCircuit#1(DCElectricalTestCircuit).
(9) Theoutputdropoutvoltageisthesupplyvoltageminustheclippingvoltage.RefertoFigure15inTypicalPerformanceCharacteristics.
4 SubmitDocumentationFeedback Copyright©1995–2013,TexasInstrumentsIncorporated
ProductFolderLinks:LM3876
LM3876
www.ti.com SNAS090D–APRIL1995–REVISEDMARCH2013
Electrical Characteristics (1)(2) (continued)
ThefollowingspecificationsapplyforV+=+35V,V−=−35V,I =−0.5mAwithR =8Ωunlessotherwisespecified.Limits
MUTE L
applyforT =25°C.
A
LM3876 Units
Parameter TestConditions
Typical(3) Limit(4) (Limits)
Ppk=100W,A-Weighted, 122 dB
Measuredat1kHz,R =25Ω
S
IMD IntermodulationDistortionTest 60Hz,7kHz,4:1(SMPTE) 0.004 %
60Hz,7kHz,1:1(SMPTE) 0.006
Test Circuit #1 (DC Electrical Test Circuit)
Test Circuit #2 (AC Electrical Test Circuit)
Copyright©1995–2013,TexasInstrumentsIncorporated SubmitDocumentationFeedback 5
ProductFolderLinks:LM3876
LM3876
SNAS090D–APRIL1995–REVISEDMARCH2013 www.ti.com
Single Supply Application Circuit
*Optionalcomponentsdependentuponspecificdesignrequirements.RefertotheExternalComponentsDescription
foracomponentfunctionaldescription.
Figure3. TypicalSingleSupplyAudioAmplifierApplicationCircuit
6 SubmitDocumentationFeedback Copyright©1995–2013,TexasInstrumentsIncorporated
ProductFolderLinks:LM3876
LM3876
www.ti.com SNAS090D–APRIL1995–REVISEDMARCH2013
Equivalent Schematic
(excludingactiveprotectioncircuitry)
Copyright©1995–2013,TexasInstrumentsIncorporated SubmitDocumentationFeedback 7
ProductFolderLinks:LM3876
LM3876
SNAS090D–APRIL1995–REVISEDMARCH2013 www.ti.com
(excludingactiveprotectioncircuitry)
External Components Description
(SeeFigure1andFigure3)
Components FunctionalDescription
1. R Actsasavolumecontrolbysettingthevoltagelevelallowedtotheamplifier'sinputterminals.
IN
2. R ProvidesDCvoltagebiasingforthesinglesupplyoperationandbiascurrentforthepositiveinputterminal.
A
3. C Providesbiasfiltering.
A
4. C ProvidesACcouplingattheinputandoutputoftheamplifierforsinglesupplyoperation.
5. R Preventscurrentsfromenteringtheamplifier'snon-invertinginputwhichmaybepassedthroughtotheloadupon
B
power-downofthesystemduetothelowinputimpedanceofthecircuitrywhentheunder-voltagecircuitryisoff.This
phenomenonoccurswhenthesupplyvoltagesarebelow1.5V.
6. C (1) Reducesthegain(bandwidthoftheamplifier)athighfrequenciestoavoidquasi-saturationoscillationsoftheoutput
C
transistor.Thecapacitoralsosuppressesexternalelectromagneticswitchingnoisecreatedfromfluorescentlamps.
7. Ri InvertinginputresistancetoprovideACGaininconjunctionwithR .
f1
8. Ci (1) Feedbackcapacitor.EnsuresunitygainatDC.Alsoalowfrequencypole(highpassroll-off)at:
f =1/(2πRiCi)
c
9. R FeedbackresistancetoprovideACGaininconjunctionwithRi.
f1
10. R (1) AthigherfrequenciesfeedbackresistanceworkswithC toprovidelowerACGaininconjunctionwithR andRi.Ahigh
f2 f f1
frequencypole(lowpassroll-off)existsat:
f =[R R (s+1/R C)]/[(R +R )(s+1/C(R +R ))]
c f1 f2 f2 f f1 f2 f f1 f2
11. C(1) CompensationcapacitorthatworkswithR andR toreducetheACGainathigherfrequencies.
f f1 f2
12. R Muteresistancesetuptoallow0.5mAtobedrawnfrompin8toturnthemutingfunctionoff.
M
→R iscalculatedusing:R ≤(|V |−2.6V)/I8whereI8≥0.5mA.RefertoFigure32inTypicalPerformance
M M EE
Characteristics.
13. C Mutecapacitancesetuptocreatealargetimeconstantforturn-onandturn-offmuting.
M
14. R (1) WorkswithC tostabilizetheoutputstagebycreatingapolethateliminateshighfrequencyoscillations.
SN SN
15. C (1) WorkswithR tostabilizetheoutputstagebycreatingapolethateliminateshighfrequencyoscillations.
SN SN
f =1/(2πR C )
c SN SN
16. L (1) ProvideshighimpedanceathighfrequenciessothatRmaydecoupleahighlycapacitiveload
17. R (1) andreducetheQoftheseriesresonantcircuitduetocapacitiveload.Alsoprovidesalowimpedanceatlow
frequenciestoshortoutRandpassaudiosignalstotheload.
18. C Providespowersupplyfilteringandbypassing.
S
19. S1 Muteswitchthatmutesthemusicgoingintotheamplifierwhenopened.
(1) Optionalcomponentsdependentuponspecificdesignrequirements.RefertoApplicationInformationformoreinformation.
OPTIONAL EXTERNAL COMPONENT INTERACTION
Although the optional external components have specific desired functions that are designed to reduce the
bandwidth and eliminate unwanted high frequency oscillations they may cause certain undesirable effects when
theyinteract.Interactionmayoccurforcomponentswhosereactancesareincloseproximitytooneanother.One
examplewouldbethecouplingcapacitor,C ,andthecompensationcapacitor, Cf.Thesetwocomponentsact as
C
low impedances to certain frequencies which will couple signals from the input to the output. Please take careful
noteofbasicamplifiercomponentfunctionalitywhendesigninginthesecomponents.
The optional external components shown in Figure 3 and described above are applicable in both single and split
voltagesupplyconfigurations.
8 SubmitDocumentationFeedback Copyright©1995–2013,TexasInstrumentsIncorporated
ProductFolderLinks:LM3876
LM3876
www.ti.com SNAS090D–APRIL1995–REVISEDMARCH2013
Typical Performance Characteristics
SPiKe
SafeArea ProtectionResponse
Figure4. Figure5.
SupplyCurrentvs PulseThermal
SupplyVoltage Resistance
Figure6. Figure7.
PulseThermal SupplyCurrentvs
Resistance OutputVoltage
Figure8. Figure9.
Copyright©1995–2013,TexasInstrumentsIncorporated SubmitDocumentationFeedback 9
ProductFolderLinks:LM3876
LM3876
SNAS090D–APRIL1995–REVISEDMARCH2013 www.ti.com
Typical Performance Characteristics (continued)
PulsePowerLimit PulsePowerLimit
Figure10. Figure11.
SupplyCurrentvs
CaseTemperature PulseResponse
Figure12. Figure13.
InputBiasCurrentvs ClippingVoltagevs
CaseTemperature SupplyVoltage
Figure14. Figure15.
10 SubmitDocumentationFeedback Copyright©1995–2013,TexasInstrumentsIncorporated
ProductFolderLinks:LM3876