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BSNANDBSPCAPACITORS
BSNANDBSPRESISTORS
VCLAMPCAPACITOR
MIDRAILBYPASSCAPACITOR
VREFDECOUPLINGCAPACITOR
DIFFERENTIALINPUT
SWITCHINGFREQUENCY
f
s
6.6
R
OSC
C
OSC
(7)
SHUTDOWNOPERATION
TPA3007D1
SLOS418A–SEPTEMBER2003–REVISEDDECEMBER2004
thefullh-bridgeoutputstageusesonlynmostransistors.itthereforerequiresbootstrapcapacitorsforthehigh
sideofeachoutputtoturnoncorrectly.a0.22-µfceramiccapacitor,ratedforatleast25v,mustbeconnected
fromeachoutputtoitscorrespondingbootstrapinput.specifically,one0.22-µfcapacitormustbeconnected
fromoutptobsp,andone0.22-µfcapacitormustbeconnectedfromoutntobsn.(seefigure13.)
tolimitthecurrentwhenchargingthebootstrapcapacitors,aresistorwithavalueof51
Ω
(+/-10%maximum)
mustbeplacedinserieswitheachbootstrapcapacitor.thecurrentislimitedtolessthan500µa.
toensurethatthemaximumgate-至-sourcevoltageforthenmosoutputtransistorsisnotexceeded,aninternal
regulatorclampsthegatevoltage.a1-µfcapacitormustbeconnectedfromvclamp(pin7)togroundand
mustberatedforatleast25v.thevoltageatvclamp(pin7)varieswithv
CC
andmaynotbeusedfor
poweringanyothercircuitry.
themidrailbypasscapacitor(c11offigure13)isthemostcriticalcapacitorandservesseveralimportant
功能.duringstart-uporrecoveryfromshutdownmode,c
绕过
determinestherateatwhichtheamplifier
startsup.thesecondfunctionistoreducenoiseproducedbythepowersupplycausedbycouplingintothe
outputdrivesignal.thisnoiseisfromthemidrailgenerationcircuitinternaltotheamplifier,whichappearsas
degradedpsrrandthd+n.
bypasscapacitor(c11)valuesof0.47-µfto1-µfceramicortantalumlow-esrcapacitorsarerecommendedfor
thebestthdnoise,anddepopperformance.thebypasscapacitor
必须
beavaluegreaterthantheinput
capacitorsforoptimumdepopperformance.
thevrefterminal(pin23)istheoutputofaninternally-generated5-vsupply,usedfortheoscillatorandgain
settinglogic.itrequiresa0.1-µfto1-µfcapacitortogroundtokeeptheregulatorstable.theregulatormaynot
beusedtopoweranyadditionalcircuitry.
thedifferentialinputstageoftheamplifiercancelsanynoisethatappearsonbothinputlinesofthechannel.至
usethetpa3007d1evmwithadifferentialsource,connectthepositiveleadoftheaudiosourcetotheinp
inputandthenegativeleadfromtheaudiosourcetotheinninput.tousethetpa3007d1withasingle-结束
源,acgroundtheinninputthroughacapacitorandapplytheaudiosignaltotheinpinput.ina
单独的-endedinputapplication,theinninputshouldbeac-groundedattheaudiosourceinsteadofatthedevice
inputforbestnoiseperformance.
TheswitchingfrequencyisdeterminedusingthevaluesofthecomponentsconnectedtoR
OSC
(pin20)andc
OSC
(pin21)andmaybecalculatedwiththefollowingequation:
Thefrequencymaybevariedfrom225kHzto275kHzbyadjustingthevalueschosenforR
OSC
andC
OSC
.
thetpa3007d1employsashutdownmodeofoperationdesignedtoreducesupplycurrent(i
CC
)totheabsolute
minimumlevelduringperiodsofnonuseforbattery-powerconservation.theshutdowninputterminalshould
beheldhighduringnormaloperationwhentheamplifierisinuse.pullingshutdownlowcausestheoutputsto
muteandtheamplifiertoenteralow-currentstate,i
cc(sd)
=1µa.shutdownshouldneverbeleft
unconnected,becauseamplifieroperationwouldbeunpredictable.
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