www.德州仪器.com
APPLICATIONINFORMATION
电容
inputcapacitor(c
在
)
outputcapacitor(c
输出
)
等效串联电阻 −
Ω
加载 电流 − 毫安
等效串联电阻 −
Ω
加载 电流 − 毫安
等效串联电阻 −
Ω
加载 电流 − 毫安
等效串联电阻 −
Ω
加载 电流 − 毫安
LP2981
100-maultra-lowdropoutregulator
WITHSHUTDOWN
SLVS521C–JULY2004–REVISEDAUGUST2005
Aminimumvalueof1
µ
f(overtheentireoperatingtemperaturerange)isrequiredattheinputofthelp2981.在
增加,thisinputcapacitorshouldbelocatedwithin1cmoftheinputpinandconnectedtoacleananalog
地面.thereisnoequivalentseriesresistance(等效串联电阻)requirementforthiscapacitor,andthecapacitancecan
beincreasedwithoutlimit.agoodqualityceramicortantalumcapacitorcanbeused.
asapnpregulator,thelp2981requirestheoutputcapacitortomeetbothaminimumcapacitanceandesr
值.requiredesrvaluesasafunctionofloadcurrentareprovidedforvariousoutputvoltages,loadcurrents,
andcapacitances(seefigures1–4).
•
MinimumC
输出
:3.3
µ
f(canbeincreasedwithoutlimittoimprovetransientresponsestabilitymargin)
•
esrrange:看Figure2通过Figure5
ItiscriticalthatboththeminimumcapacitanceandESRrequirementbemetovertheentireoperating
temperaturerange.dependingonthetypeofcapacitorused,bothoftheseparameterscanvarysignificantlywith
温度(seecapacitorcharacteristicssection).
figure2.5-v/3.3-
µ
fesrcurvesfigure3.5-v/10-
µ
FESRCurves
figure4.3-v/3.3-
µ
fesrcurvesfigure5.3-v/10-
µ
FESRCurves
6