Datasheet

DESCRIPTION/ORDERINGINFORMATION
TCA6408A
SCPS192C–APRIL2009–REVISEDJULY2009............................................................................................................................................................. www.ti.com
This8-bitI/Oexpanderforthetwo-linebidirectionalbus(I
2
C)isdesignedtoprovidegeneral-purposeremoteI/O
expansionformostmicrocontrollerfamiliesviatheI
2
Cinterface[serialclock(SCL)andserialdata(SDA)].
ThemajorbenefitofthisdeviceisitswideV
CC
range.Itcanoperatefrom1.65-Vto5.5-VontheP-portsideand
ontheSDA/SCLside.ThisallowstheTCA6408Atointerfacewithnext-generationmicroprocessorsand
microcontrollersontheSDA/SCLside,wheresupplylevelsaredroppingdowntoconservepower.Incontrastto
thedroppingpowersuppliesofmicroprocessorsandmicrocontrollers,somePCBcomponentssuchasLEDs
remainata5-Vpowersupply.
Thebidirectionalvoltage-leveltranslationintheTCA6408AisprovidedthroughV
CCI
.V
CCI
shouldbeconnectedto
theV
CC
oftheexternalSCL/SDAlines.ThisindicatestheV
CC
leveloftheI
2
CbustotheTCA6408A.Thevoltage
levelonthePportoftheTCA6408AisdeterminedbyV
CCP
.
TheTCA6408Aconsistsofone8-bitConfiguration(inputoroutputselection),Input,Output,andPolarity
Inversion(activehigh)Register.Atpoweron,theI/Osareconfiguredasinputs.However,thesystemmastercan
enabletheI/OsaseitherinputsoroutputsbywritingtotheI/Oconfigurationbits.Thedataforeachinputor
outputiskeptinthecorrespondingInputorOutputRegister.ThepolarityoftheInputPortRegistercanbe
invertedwiththePolarityInversionRegister.Allregisterscanbereadbythesystemmaster.
ThesystemmastercanresettheTCA6408Aintheeventofatimeoutorotherimproperoperationbyassertinga
lowintheRESETinput.Thepower-onresetputstheregistersintheirdefaultstateandinitializestheI
2
C/SMBus
statemachine.TheRESETpincausesthesamereset/initializationtooccurwithoutdepoweringthepart.
TheTCA6408Aopen-draininterrupt(INT)outputisactivatedwhenanyinputstatediffersfromitscorresponding
InputPortRegisterstateandisusedtoindicatetothesystemmasterthataninputstatehaschanged.
INTcanbeconnectedtotheinterruptinputofamicrocontroller.Bysendinganinterruptsignalonthisline,the
remoteI/Ocaninformthemicrocontrollerifthereisincomingdataonitsportswithouthavingtocommunicatevia
theI
2
Cbus.Thus,theTCA6408Acanremainasimpleslavedevice.
ThedeviceP-portoutputshavehigh-currentsinkcapabilitiesfordirectlydrivingLEDswhileconsuminglow
devicecurrent.
Onehardwarepin(ADDR)canbeusedtoprogramandvarythefixedI
2
Caddressandallowuptotwodevicesto
sharethesameI
2
CbusorSMBus.
ORDERINGINFORMATION
T
A
PACKAGE
(1)(2)
ORDERABLEPARTNUMBERTOP-SIDEMARKING
QFN–RGTReelof3000TCA6408ARGTRZVU
–40°Cto85°CTSSOP–PWReelof2000TCA6408APWRPH408A
µQFN–RSVReelof3000TCA6408ARSVRZVU
(1)Packagedrawings,thermaldata,andsymbolizationareavailableatwww.ti.com/packaging.
(2)Forthemostcurrentpackageandorderinginformation,seethePackageOptionAddendumattheendofthisdocument,orseetheTI
websiteatwww.ti.com.
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ProductFolderLink(s):TCA6408A