Datasheet

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DESCRIPTION/ORDERINGINFORMATION(CONTINUED)
PCA9548A
8-CHANNELI
2
CSWITCH
WITHRESET
SCPS143C–OCTOBER2006–REVISEDJUNE2007
ThePCA9548AhaseightbidirectionaltranslatingswitchesthatcanbecontrolledviatheI
2
Cbus.TheSCL/SDA
upstreampairfansouttoeightdownstreampairs,orchannels.AnyindividualSCx/SDxchannelorcombination
ofchannelscanbeselected,determinedbythecontentsoftheprogrammablecontrolregister.
ThesystemmastercanresetthePCA9548Aintheeventofatimeoutorotherimproperoperationbyassertinga
lowintheRESETinput.Similarly,thepower-onresetdeselectsallchannelsandinitializestheI
2
C/SMBusstate
machine.AssertingRESETcausesthesamereset/initializationtooccurwithoutdepoweringthepart.
ThepassgatesoftheswitchesareconstructedsothattheV
CC
pincanbeusedtolimitthemaximumhigh
voltage,whichispassedbythePCA9548A.Thisallowstheuseofdifferentbusvoltagesoneachpair,sothat
2.5-Vor3.3-Vpartscancommunicatewith5-Vparts,withoutanyadditionalprotection.Externalpullupresistors
pullthebusuptothedesiredvoltagelevelforeachchannel.AllI/Opinsare5-Vtolerant.
2
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