300mA的超低噪声小封装超高速CMOS LDO稳压器LP3984Word文件下载.docx
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1.8V
25:
2.5V
28:
2.8V
2H:
2.85V
30:
3.0V
33:
3.3V
Features
◆Ultra-Low-NoiseforRFApplication
◆2V-6.5VInputVoltageRange
◆LowDropout:
200mV@300mA
◆1.2V,1.3V,1.5V,1.8V,2.5V,2.8V3.0Vand3.3VFixed
◆300mAOutputCurrent,550mAPeakCurrent
◆HighPSSR:
-73dBat1KHz
◆<
0.01uAStandbyCurrentWhenShutdown
◆AvailableinSOT23-5Package
◆TTL-Logic-ControlledShutdownInput
◆Ultra-FastResponseinLine/Loadtransient
◆CurrentLimitingandThermalShutdownProtection
◆Quickstart-up（typically50uS）
TypicalApplicationCircuit
Applications
✧PortableMediaPlayers/MP3players
✧CellularandSmartmobilephone
✧LCD
✧DSCSensor
✧WirelessCard
PinConfigurations
SOT23-5
MarkingInformation
Device
Marking
Package
Shipping
LP3984
XXXX
3K/REEL
FunctionalPinDescription
Pinnumber
PinName
PinFunction
1
VIN
PowerInputVoltage.
2
GND
Ground.
3
EN
ChipEnable（ActiveHigh）.Notethatthispinishighimpedance.Thereshouldbeapulllow100kΩresistorconnectedtoGNDwhenthecontrolsignalisfloating.
4
BP
ReferenceNoiseBypass.
5
VOUT
OutputVoltage.
FunctionBlockDiagram
AbsoluteMaximumRatings
SupplyInputVoltage----------------------------------------------------------------------------------------------------------6.5V
PowerDissipation,PD@TA=25°
C
SOT23-5-------------------------------------------------------------------------------------------------------------------400mW
PackageThermalResistance
SOT23-5,θJA----------------------------------------------------------------------------------------------------------250°
C/W
LeadTemperature（Soldering,10sec.）-----------------------------------------------------------------------------260°
StorageTemperatureRange-----------------------------------------------------------------------------−65°
Cto150°
ESDSusceptibility
HBM（HumanBodyMode）------------------------------------------------------------------------------------------------2kVMM（Machine-Mode）--------------------------------------------------------------------------------------------------------200V
RecommendedOperatingConditions
SupplyInputVoltage----------------------------------------------------------------------------------------------2.5Vto5.5V
ENInputVoltage-----------------------------------------------------------------------------------------------------0Vto5.5V
OperationJunctionTemperatureRange----------------------------------------------------------------−40°
Cto125°
OperationAmbientTemperatureRange-------------------------------------------------------------------−40°
Cto85°
ElectricalCharacteristics
（VIN=VOUT+1V,CIN=COUT=1µ
F,CBP=22nF,TA=25°
C,unlessotherwisespecified）
Parameter
Symbol
TestConditions
Min
Typ.
Max
Units
OutputVoltageAccuracy
ΔVOUT
IOUT=1mA
−2
--
+2
%
OutputLoadingCurrent
ILOAD
VEN=VIN,VIN>
2.5V
300
mA
CurrentLimit
ILIM
RLOAD=1Ω
360
400
QuiescentCurrent
IQ
VEN≥1.2V,IOUT=0mA
75
130
μA
DropoutVoltage
VDROP
IOUT=200mA,VOUT>
120
150
mV
IOUT=300mA,VOUT>
200
260
LineRegulation
ΔVLINE
VIN=（VOUT+1V）to5.5V,IOUT=1mA
0.3
LoadRegulation
ΔLOAD
1mA<
IOUT<
300mA
0.6
StandbyCurrent
ISTBY
VEN=GND,Shutdown
0.01
ENInputBiasCurrent
IIBSD
VEN=GNDorVIN
0.1
100
nA
ENThreshold
Logic-LowVoltage
VIL
VIN=3Vto5.5V,Shutdown
0.4
V
Logic-HighVoltage
VIH
VIN=3Vto5.5V,Start-Up
1.4
OutputNoiseVoltage
10Hzto100kHz,IOUT=200mACOUT=1µ
F
uVRMS
PowerSupply
f=100Hz
PSRR
−76
dB
RejectionRate
f=10kHz
COUT=1µ
F,
IOUT=10mA
−68
ThermalShutdownTemperature
TSD
165
°
C
TypicalOperatingCharacteristics
ILoad=200mA
ApplicationsInformation
Likeanylow-dropoutregulator,theexternalcapacitorsusedwiththeLP3984mustbecarefullyselectedforregulatorstabilityandperformance.Usingacapacitorwhosevalueis>
1µ
FontheLP3984inputandtheamountofcapacitancecanbeincreasedwithoutlimit.Theinputcapacitormustbelocatedadistanceofnotmorethan0.5inchfromtheinputpinoftheICandreturnedtoacleananalogground.Anygoodqualityceramicortantalumcanbeusedforthiscapacitor.ThecapacitorwithlargervalueandlowerESR（equivalentseriesresistance）providesbetterPSRRandline-transientresponse.TheoutputcapacitormustmeetbothrequirementsforminimumamountofcapacitanceandESRinallLDOsapplication.TheLP3984isdesignedspecificallytoworkwithlowESRceramicoutputcapacitorinspace-savingandperformanceconsideration.Usingaceramiccapacitorwhosevalueisatleast1µ
FwithESRis>
25mΩontheLP3984outputensuresstability.TheLP3984stillworkswellwithoutputcapacitorofothertypesduetothewidestableESRrange.Figure1showsthecurvesofallowableESRrangeasafunctionofloadcurrentforvariousoutputcapacitorvalues.Outputcapacitoroflargercapacitancecanreducenoiseandimproveloadtransientresponse,stability,andPSRR.Theoutputcapacitorshouldbelocatednotmorethan0.5inchfromtheVOUTpinoftheLP3984andreturnedtoacleananalogground.
Start-upFunctionEnableFunction
TheLP3984featuresanLDOregulatorenable/disablefunction.ToassuretheLDOregulatorwillswitchon,theENturnoncontrollevelmustbegreaterthan1.4volts.TheLDOregulatorwillgointotheshutdownmodewhenthevoltageontheENpinfallsbelow0.4volts.Fortoprotectingthesystem,theLP3984haveaquick-dischargefunction.Iftheenablefunctionisnotneededinaspecificapplication,itmaybetiedtoVINtokeeptheLDOregulatorinacontinuouslyonstate.
BypassCapacitorandLowNoise
Connectinga22nFbetweentheBPpinandGNDpinsignificantlyreducesnoiseontheregulatoroutput,itiscriticalthatthecapacitorconnectionbetweentheBPpinandGNDpinbedirectandPCBtracesshouldbeasshortaspossible.ThereisarelationshipbetweenthebypasscapacitorvalueandtheLDOregulatorturnontime.DCleakageonthispincanaffecttheLDOregulatoroutputnoiseandvoltageregulationperformance.
ThermalConsiderations
ThermalprotectionlimitspowerdissipationinLP3984.Whentheoperationjunctiontemperatureexceeds165°
C,theOTPcircuitstartsthethermalshutdownfunctionturnthepasselementoff.Thepasselementturnsonagainafterthejunctiontemperaturecoolsby30°
C.Forcontinueoperation,donotexceedabsolutemaximumoperationjunctiontemperature125°
C.
Thepowerdissipationdefinitionindeviceis:
PD=（VIN−VOUT）xIOUT+VINxIQ
ThemaximumpowerdissipationdependsonthethermalresistanceofICpackage,PCBlayout,therateofsurroundingsairflowandtemperaturedifferencebetweenjunctiontoambient.
Themaximumpowerdissipationcanbecalculatedbyfollowingformula:
PD（MAX）=（TJ（MAX）−TA）/θJA
Where
TJ（MAX）isthemaximumoperationjunctiontemperature125°
C,TAistheambienttemperatureandtheθJAisthejunctiontoambientthermalresistance.ForrecommendedoperatingconditionsspecificationofLP3984,where
TJ（MAX）isthemaximumjunctiontemperatureofthedie（125°
C）andTAisthemaximumambienttemperature.Thejunctiontoambientthermalresistance（θJAislayoutdependent）forSOT23-5packageis250°
C/W.
PD（MAX）=（125°
C−25°
C）/250=400mW（SOT23-5）PD（MAX）=（125°
C）/165=606mW（withPCBPAD）
ThemaximumpowerdissipationdependsonoperatingambienttemperatureforfixedTJ（MAX）andthermalresistanceθJA.
PackagingInformation
升级会员 