Datasheet

R3
100k
EN
SDAIN
SCLIN
V
GND
CC
SDAOUT
SCLOUT
READY
EN
SDAIN
SCLIN
V
GND
CC
SDAOUT
SCLOUT
READY
R9
10k
R8
10k
R10
10k
I/OPeripheralCard2
TCA4311
CARD2_SCL
CARD2_SDA
R5
10k
R4
10k
I/OPeriperalCard1
TCA4311
C20.1 Fµ
R7
100k
C40.1 Fµ
CARD_SCL
CARD_SDA
R1
10k
V
CC
R2
10k
Backplane
Backplane
Connector
SDA
SCL
C1
0.01 Fµ
C3
0.01
Fµ
R6
10k
•
•
•
Repeater/BusExtenderApplication
TCA4311
SCPS173–DECEMBER2008........................................................................................................................................................................................... www.ti.com
Figure13showstheTCA4311inaPCIapplication,whereallofthepinshavethesamelength.Inthiscase,
connectanRCseriescircuitontheI/OcardbetweenV
CC
andEN.AnRCproductof10msprovidesafilterto
preventtheTCA4311frombecomingactivateduntilthetransientsassociatedwithliveinsertionhavesettled.
Figure13.InsertingMultipleI/OCardsintoaLiveBackplaneUsingtheTCA4311inaPCISystem
Userswhowishtoconnecttwo2-wiresystemsseparatedbyadistancecandosobyconnectingtwoTCA4311
back-to-back,asshowninFigure14.TheI
2
Cspecificationallowsfor400pFmaximumbuscapacitance,
severelylimitingthelengthofthebus.TheSMBusspecificationplacesnorestrictiononbuscapacitance,butthe
limitedimpedancesofdevicesconnectedtothebusrequiresystemstoremainsmallifrise-andfall-time
specificationsaretobemet.ThestrongpullupandpulldownimpedancesoftheTCA4311arecapableofmeeting
rise-andfall-timespecificationsforonenanofaradofcapacitance,thusallowingmuchmoreinterconnect
distance.Inthissituation,thedifferentialgroundvoltagebetweenthetwosystemsmaylimitthealloweddistance,
becauseavalidlogiclowvoltagewithrespecttothegroundatoneendofthesystemmayviolatetheallowed
V
OL
specificationwithrespecttothegroundattheotherend.Inaddition,theconnectioncircuitryoffsetvoltages
oftheback-to-backTCA4311addtogether,directlycontributingtothesameproblem.
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ProductFolderLink(s):TCA4311
Not Recommended For New Designs