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PCBLayoutConsiderations
bq24030,bq24031,bq24032,
bq24032a,bq24035,bq24038,bq24039
SLUS618C–AUGUST2004–REVISEDJUNE2005
applicationinformation(持续)
itisimportanttopayspecialattentiontothepcblayout.thefollowingprovidessomeguidelines:
•
toobtainoptimalperformance,thedecouplingcapacitorfrominputterminalstovssandtheoutputfilter
capacitorsfromouttovssshouldbeplacedascloseaspossibletothebqtiny-ii,withshorttracerunsto
bothsignalandvsspins.
•
alllow-currentvssconnectionsshouldbekeptseparatefromthehigh-currentchargeordischargepaths
fromthebattery.useasingle-pointgroundtechniqueincorporatingboththesmallsignalgroundpathandthe
powergroundpath.
•
thehigh-currentchargepathsintoacandusbandfromthebatandoutpinsmustbesized
appropriatelyforthemaximumchargecurrentinordertoavoidvoltagedropsinthesetraces.
•
thebqtiny-iiiispackagedinathermallyenhancedmlppackage.thepackageincludesaqfnthermal
padtoprovideaneffectivethermalcontactbetweenthedeviceandtheprinted-circuitboard.fullpcbdesign
guidelinesforthispackageareprovidedintheapplicationnoteentitled
qfn/sonpcbattachment
(SLUA271).
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