LM4780 Overture Audio Pwr Amp Series Stereo 60W, Mono 120W Audio Pwr Amp w/Mute

32 Pages·2017·1.3 MB·English

LM4780, LM4780TABD
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LM4780 Overture™ Audio Power Amplifier Series Stereo 60W, Mono 120W Audio Power
Amplifier with Mute
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FEATURES DESCRIPTION
1
• SPiKeProtection The LM4780 is a stereo audio amplifier capable of
23 typically delivering 60W per channel of continuous
• LowExternalComponentCount
average output power into an 8Ω load with less than
• QuietFade-In/OutMuteMode 0.5% THD+Nfrom20Hz-20kHz.
• WideSupply Range:20V-84V
The LM4780 is fully protected utilizing Texas
• Signal-to-NoiseRatio≥97dB(ref.toP =1W) Instruments' Self Peak Instantaneous Temperature
O
(°Ke) (SPiKeTM) protection circuitry. SPiKe provides a
APPLICATIONS dynamically optimized Safe Operating Area (SOA).
SPiKe protection completely safeguards the
• AudioAmplifier forComponentStereo
LM4780's outputs against over-voltage, under-
• AudioAmplifier forCompactStereo voltage, overloads, shorts to the supplies or GND,
• AudioAmplifier forSelf-PoweredSpeakers thermal runaway and instantaneous temperature
peaks. The advanced protection features of the
• AudioAmplifier forHigh-Endand HDTVs
LM4780placesitinaclassabovediscreteandhybrid
amplifiers.
KEY SPECIFICATIONS
Each amplifier of the LM4780 has an independent
• Output Power/Channelwith0.5%THD+N, 1kHz
smoothtransitionfade-in/outmute.
into8Ω:60W(Typ)
The LM4780 can easily be configured for bridge or
• THD+Nat2x30Winto8Ω(20Hz-20kHz):
paralleloperationfor 120Wmonosolutions.
0.03%(Typ)
• THD+Nat2x30Winto6Ω(20Hz-20kHz):
0.05%(Typ)
• THD+Nat2x30Winto4Ω(20Hz-20kHz):
0.07%(Typ)
• MuteAttenuation:110dB (Typ)
• PSRR:85dB(Min)
• SlewRate:19V/µs(Typ)
1
Pleasebeawarethatanimportantnoticeconcerningavailability,standardwarranty,anduseincriticalapplicationsof
TexasInstrumentssemiconductorproductsanddisclaimerstheretoappearsattheendofthisdatasheet.
OvertureisatrademarkofTexasInstruments.
2
Allothertrademarksarethepropertyoftheirrespectiveowners.
3
PRODUCTIONDATAinformationiscurrentasofpublicationdate. Copyright©2003–2013,TexasInstrumentsIncorporated
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarilyincludetestingofallparameters.
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Typical Application
Figure1. TypicalAudioAmplifierApplicationCircuit
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Connection Diagram
Figure2. TO-220PlasticPackage(TopView)(1)
SeePackageNumber NDM0027A
(1) TheNDM0027Aisanon-isolatedpackage.Thepackage'smetalback,andanyheatsinktowhichitismountedareconnectedtotheV-
potentialwhenusingonlythermalcompound.Ifamicawasherisusedinadditiontothermalcompound,θ (casetosink)isincreased,
CS
buttheheatsinkwillbeelectricallyisolatedfromV-.
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Absolute Maximum Ratings(1)(2)(3)
SupplyVoltage|V+|+|V-|(NoSignal) 94V
SupplyVoltage|V+|+|V-|(InputSignal) 84V
CommonModeInputVoltage (V+orV-)and|V+|+|V-|≤80V
DifferentialInputVoltage(4) 60V
OutputCurrent InternallyLimited
PowerDissipation(5) 125W
ESDSusceptability(6) 3.0kV
ESDSusceptability(7) 200V
JunctionTemperature(T )(8) 150°C
JMAX
SolderingInformation TAPackage(10seconds) 260°C
StorageTemperature -40°Cto+150°C
θ 30°C/W
JA
ThermalResistance
θ 0.8°C/W
JC
(1) AbsoluteMaximumRatingsindicatelimitsbeyondwhichdamagetothedevicemayoccur.OperatingRatingsindicateconditionsfor
whichthedeviceisfunctional,butdonotensurespecificperformancelimits.ElectricalCharacteristicsstateDCandACelectrical
specificationsunderparticulartestconditionswhichensurespecificperformancelimits.Thisassumesthatthedeviceiswithinthe
OperatingRatings.Specificationsarenotspecifiedforparameterswherenolimitisgiven;however,thetypicalvalueisagoodindication
ofdeviceperformance.
(2) Allvoltagesaremeasuredwithrespecttothegroundpins,unlessotherwisespecified.
(3) IfMilitary/Aerospacespecifieddevicesarerequired,pleasecontacttheTexasInstrumentsSalesOffice/Distributorsforavailabilityand
specifications.
(4) TheDifferentialInputVoltageAbsoluteMaximumRatingisbasedonsupplyvoltagesV+=40VandV-=-40V.
(5) Themaximumpowerdissipationmustbede-ratedatelevatedtemperaturesandisdictatedbyT ,θ ,andtheambienttemperature
JMAX JC
T .ThemaximumallowablepowerdissipationisP =(T -T )/θ orthenumbergivenintheAbsoluteMaximumRatings,
A DMAX JMAX A JC
whicheverislower.FortheLM4780,T =150°Candthetypicalθ is0.8°C/W.RefertotheTHERMALPROTECTIONsectionfor
JMAX JC
moreinformation.
(6) Humanbodymodel,100pFdischargedthrougha1.5kΩresistor.
(7) MachineModel:a220pF-240pFdischargedthroughallpins.
(8) Themaximumoperatingjunctiontemperatureis150°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-| 20V≤V ≤84V
TOTAL
(1) Allvoltagesaremeasuredwithrespecttothegroundpins,unlessotherwisespecified.
(2) AbsoluteMaximumRatingsindicatelimitsbeyondwhichdamagetothedevicemayoccur.OperatingRatingsindicateconditionsfor
whichthedeviceisfunctional,butdonotensurespecificperformancelimits.ElectricalCharacteristicsstateDCandACelectrical
specificationsunderparticulartestconditionswhichensurespecificperformancelimits.Thisassumesthatthedeviceiswithinthe
OperatingRatings.Specificationsarenotspecifiedforparameterswherenolimitisgiven;however,thetypicalvalueisagoodindication
ofdeviceperformance.
(3) Operationisspecifiedupto84V;however,distortionmaybeintroducedfromSPiKeprotectioncircuitryifproperthermalconsiderations
arenottakenintoaccount.RefertotheTHERMALPROTECTIONsectionformoreinformation.
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Electrical Characteristics(1)(2)
ThefollowingspecificationsapplyforV+=+35V,V-=−35V,I =-1mAandR =8Ωunlessotherwisespecified.Limits
MUTE L
applyforT =25°C.
A
LM4780 Units
Symbol Parameter Conditions
Typical(3) Limit(4)(5) (Limits)
|V+|+|V-| PowerSupplyVoltage(6) GND−V-≥9V 18 20 V(min)
84 V(max)
A MuteAttenuation I =0mA 110 80 dB(min)
M MUTE
THD+N=0.5%(max)
f=1kHz;f=20kHz
P OutputPower(RMS) |V+|=|V-|=25V,R =4Ω 55 50 W(min)
O L
|V+|=|V-|=30V,R =6Ω 55 50 W(min)
L
|V+|=|V-|=35V,R =8Ω 60 50 W(min)
L
P =30W,f=20Hz-20kHz
O
A =26dB
THD+N TotalHarmonicDistortion+ |VV+|=|V-|=25V,R =4Ω 0.07 %
Noise |V+|=|V-|=30V,RL=6Ω 0.05 %
L
|V+|=|V-|=35V,R =8Ω 0.03 %
L
P =10W,f=1kHz 70 dB
X ChannelSeparation(7) O
talk
P =10W,f=10kHz 72 dB
O
SR SlewRate V =2.0V ,t =2ns 19 8 V/μs(min)
IN P-P RISE
TotalQuiescentPower V =0V, 110 170 mA(max)
CM
I
DD
SupplyCurrent V =0V,I =0A
O O
V InputOffsetVoltage V =0V,I =0mA 1 10 mV(max)
OS CM O
I InputBiasCurrent V =0V,I =0mA 0.2 1 μA(max)
B CM O
I OutputCurrentLimit |V+|=|V-|=20V,t =10ms 11.5 7 A(min)
O ON
VOD OutputDropoutVoltage(8) ||VV+---VVO|,|,VV-=+-=282V8,VI,IO==-1+0100m0AmA 12..65 23..00 VV((mmaaxx))
O O
V+=40Vto20V,V-=-40V,
120 85 dB(min)
V =0V,I =0mA
PSRR PowerSupplyRejectionRatio(9) CM O
V+=40V,V-=-40Vto-20V,
105 85 dB(min)
V =0V,I =0mA
CM O
CMRR CommonModeRejectionRatio(9) V+=60Vto20V,V-=-20Vto-60V, 110 85 dB(min)
V =20Vto-20V,I =0mA
CM O
A OpenLoopVoltageGain R =2kΩ,ΔV =40V 115 90 dB(min)
VOL L O
GBWP GainBandwidthProduct f =100kHz,V =50mV 8 2 MHz(min)
IN IN RMS
IHF-A-WeightingFilter,
e InputNoise 2.0 10 μV(max)
IN R =600Ω(InputReferred)
IN
P =1W ;A-WeightedFilter
O RMS 97 dB
f =1kHz,R =25Ω
IN S
SNR Signal-to-NoiseRatio
P =50W ;A-WeightedFilter
O RMS 114 dB
f =1kHz,R =25Ω
IN S
(1) Allvoltagesaremeasuredwithrespecttothegroundpins,unlessotherwisespecified.
(2) AbsoluteMaximumRatingsindicatelimitsbeyondwhichdamagetothedevicemayoccur.OperatingRatingsindicateconditionsfor
whichthedeviceisfunctional,butdonotensurespecificperformancelimits.ElectricalCharacteristicsstateDCandACelectrical
specificationsunderparticulartestconditionswhichensurespecificperformancelimits.Thisassumesthatthedeviceiswithinthe
OperatingRatings.Specificationsarenotspecifiedforparameterswherenolimitisgiven;however,thetypicalvalueisagoodindication
ofdeviceperformance.
(3) Typicalspecificationsaremeasuredat25°Candrepresenttheparametricnorm.
(4) TestedlimitsarespecifiedtoAOQL(AverageOutgoingQualityLevel).
(5) Datasheetmin/maxspecificationlimitsarespecifiedbydesign,test,orstatisticalanalysis.
(6) V-musthaveatleast-9VatitspinwithreferencetoGNDinorderfortheunder-voltageprotectioncircuitrytobedisabled.Inaddition,
thevoltagedifferentialbetweenV+andV-mustbegreaterthan14V.
(7) Crosstalkperformancewasmeasuredusingthedemoboardshowninthedatasheet.PCBlayoutwillaffectcrosstalk.Itis
recommendedthatinputandoutputtracesbeseparatedbyasmuchdistanceaspossible.Returngroundtracesfromoutputsshouldbe
independentbacktoasinglegroundpointanduseaswideoftracesaspossible.
(8) Theoutputdropoutvoltageisdefinedasthesupplyvoltageminustheclippingvoltage.RefertotheClippingVoltagevs.SupplyVoltage
graphintheTypicalPerformanceCharacteristicssection.
(9) DCelectricaltest.
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Electrical Characteristics(1)(2) (continued)
ThefollowingspecificationsapplyforV+=+35V,V-=−35V,I =-1mAandR =8Ωunlessotherwisespecified.Limits
MUTE L
applyforT =25°C.
A
LM4780 Units
Symbol Parameter Conditions
Typical(3) Limit(4)(5) (Limits)
60Hz,7kHz,4:1(SMPTE) 0.004 %
IMD IntermodulationDistortion
60Hz,7kHz,1:1(SMPTE) 0.009 %
Bridged Amplifier Application Circuit
Figure3. BridgedAmplifier ApplicationCircuit
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Parallel Amplifier Application Circuit
Figure4. Parallel Amplifier ApplicationCircuit
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Single Supply Application Circuit
*Optionalcomponentsdependentuponspecificdesignrequirements.
Figure5. SingleSupply Amplifier ApplicationCircuit
Auxiliary Amplifier Application Circuit
Figure6. SpecialAudioAmplifierApplicationCircuit
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External Components Description
(Figure1toFigure6)
Components FunctionalDescription
Preventscurrentfromenteringtheamplifier'snon-invertinginput.Thiscurrentmaypassthroughtotheloadduring
1 R systempowerdown,becauseoftheamplifier'slowinputimpedancewhentheundervoltagecircuitryisoff.This
B
phenomenonoccurswhentheV+andV-supplyvoltagesarebelow1.5V.
2 R Invertinginputresistance.AlongwithR,setsACgain.
i f
3 R Feedbackresistance.AlongwithR,setsACgain.
f i
Feedbackresistance.WorkswithCfandRfcreatingalowpassfilterthatlowersACgainathighfrequencies.The-
4 R (1) 3dBpointofthepoleoccurswhen:(R -R)/2=R //[1/(2πfC)+R ]fortheNon-Invertingconfigurationshownin
f2 f i f c f f2
Figure6.
5 C(1) Compensationcapacitor.WorkswithR andR toreduceACgainathigherfrequencies.
f f f2
6 C (1) Compensationcapacitor.Reducesthegainathigherfrequenciestoavoidquasi-saturationoscillationsoftheoutput
C transistor.Alsosuppressesexternalelectromagneticswitchingnoisecreatedfromfluorescentlamps.
7 C(1) FeedbackcapacitorwhichensuresunitygainatDC.AlongwithR alsocreatesahighpassfilteratf =1/(2πRC).
i i c i i
Providespowersupplyfilteringandbypassing.RefertotheSUPPLYBYPASSINGapplicationsectionforproper
8 C
S placementandselectionofbypasscapacitors.
9 R (1) Actsasavolumecontrolbysettingtheinputvoltagelevel.
V
Setstheamplifier'sinputterminalsDCbiaspointwhenC ispresentinthecircuit.AlsoworkswithC tocreatea
IN IN
10 R (1) highpassfilteratf =1/(2πR C ).IfthevalueofR istoolarge,oscillationsmaybeobservedontheoutputs
IN C IN IN IN
whentheinputsarefloating.Recommendedvaluesare10kΩto47kΩ.RefertoFigure6.
11 C (1) Inputcapacitor.Preventstheinputsignal'sDCoffsetsfrombeingpassedontotheamplifier'sinputs.
IN
12 R (1) WorkswithC tostabilizetheoutputstagebycreatingapolethatreduceshighfrequencyinstabilities.
SN SN
13 C (1) WorkswithRSNtostabilizetheoutputstagebycreatingapolethatreduceshighfrequencyinstabilities.Thepoleis
SN setatf =1/(2πR C ).RefertoFigure6.
C SN SN
14 L(1) ProvideshighimpedanceathighfrequenciessothatRmaydecoupleahighlycapacitiveloadandreducetheQof
theseriesresonantcircuit.AlsoprovidesalowimpedanceatlowfrequenciestoshortoutRandpassaudiosignals
15 R(1) totheload.RefertoFigure6.
16 R ProvidesDCvoltagebiasingforthetransistorQ1insinglesupplyoperation.
A
17 C Providesbiasfilteringforsinglesupplyoperation.
A
18 R (1) Limitsthevoltagedifferencebetweentheamplifier'sinputsforsinglesupplyoperation.RefertotheCLICKSAND
INP POPSapplicationsectionforamoredetailedexplanationofthefunctionofR .
INP
Providesinputbiascurrentforsinglesupplyoperation.RefertotheCLICKSANDPOPSapplicationsectionfora
19 R
BI moredetailedexplanationofthefunctionofR .
BI
EstablishesafixedDCcurrentforthetransistorQ1insinglesupplyoperation.Thisresistorstabilizesthehalf-
20 R
E supplypointalongwithC .
A
Muteresistancesetuptoallow0.5mAtobedrawnfromeachMUTEpintoturnthemutingfunctionoff.
21 R →R iscalculatedusing:R ≤(|V |−2.6V)/lwherel≥0.5mA.RefertotheFigure21curvesintheTypical
M M M EE
PerformanceCharacteristicssection.
22 C Mutecapacitancesetuptocreatealargetimeconstantforturn-onandturn-offmuting.
M
23 S Muteswitch.WhenopenorswitchedtoGND,theamplifierwillbeinmutemode.
1
24 R ReducescurrentflowbetweenoutputsthatarecausedbyGainorDCoffsetdifferencesbetweentheamplifiers.
OUT
(1) Optionalcomponentsdependentuponspecificdesignrequirements.
Optional External Component Interaction
The optional external components have specific desired functions. Their values are chosen to reduce the
bandwidth and eliminate unwanted high frequency oscillation. They may, however, cause certain undesirable
effects when they interact. Interaction may occur when the components produce reactions that are nearly equal
to one another. One example is the coupling capacitor, C , and the compensation capacitor, C. These two
C f
components are low impedances at certain frequencies. They may couple signals from the input to the output.
Please take careful note of basic amplifier component functionality when selecting the value of these
componentsandtheirplacementonaprintedcircuit board(PCB).
The optional external components shown in Figure 5 and Figure 6, and described above, are applicable in both
singleandsplitsupplyvoltageconfigurations.
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Typical Performance Characteristics
THD+NvsFrequency±25V,P =1W&30W/Channel THD+NvsFrequency±30V,P =1W&30W/Channel
OUT OUT
R =4Ω,80kHzBW R =6Ω,80kHzBW
L L
Figure7. Figure8.
THD+NvsFrequency±35V,P =1W&30W/Channel
OUT
R =8Ω,80kHzBW THD+NvsOutputPower/Channel±25V,R =4Ω,80kHzBW
L L
Figure9. Figure10.
THD+NvsOutputPower/Channel±30V,R =6Ω,80kHzBW THD+NvsOutputPower/Channel±35V,R =8Ω,80kHzBW
L L
Figure11. Figure12.
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