Datasheet
APPLICATIONINFORMATION
LiveInsertionandCapacitanceBufferingApplication
StaggeredConnector
R13
10k
R12
10k
R14
10k
I/OPeripheralCardN
EN
SDAIN
SCLIN
TCA4311
V
CC
GND
CARDN_SCL
CARDN_SDA
SDAOUT
SCLOUT
READY
EN
SDAIN
SCLIN
V
CC
GND
SDAOUT
SCLOUT
READY
EN
Card
Enable/Disable
SDAIN
SCLIN
V
CC
GND
SDAOUT
SCLOUT
READY
•••
R9
10k
R8
10k
R10
10k
I/OPeripheralCard2
TCA4311
CARD2_SCL
CARD2_SDA
R5
10k
R4
10k
R6
10k
I/OPeripheralCard1
TCA4311
CARD_SCL
CARD_SDA
R1
10k
V
CC
R2
10k
Backplane
Backplane
Connector
SDA
BD_SEL
SCL
C1
R3
10k
R7
10k
R11
10k
C3
0.01µF
C5
0.01µF
PowerSupply
HotSwap
PowerSupply
HotSwap
Card
Enable/Disable
Card
Enable/Disable
StaggeredConnector
StaggeredConnector
PowerSupply
HotSwap
0.01µF
TCA4311
www.ti.com
...........................................................................................................................................................................................SCPS173–DECEMBER2008
Figure12throughFigure13illustratetheusageoftheTCA4311inapplicationsthattakeadvantageofbothits
hotswapcontrollingandcapacitancebufferingfeatures.Inalloftheseapplications,notethatiftheI/Ocards
werepluggeddirectlyintothebackplane,allofthebackplaneandcardcapacitanceswouldadddirectlytogether,
makingrise-andfall-timerequirementsdifficulttomeet.PlacingaTCA4311ontheedgeofeachcard,however,
isolatesthecardcapacitancefromthebackplane.ForagivenI/Ocard,theTCA4311drivesthecapacitanceof
everythingonthecardandthebackplanemustdriveonlythecapacitanceoftheTCA4311,whichislessthan10
pF.
Figure12showstheTCA4311inaCompactPCI™configuration.ConnectV
CC
andENtotheoutputofoneofthe
CompactPCIpowersupplyHotSwapcircuits.UseapullupresistortoENforacardsideenable/disable.
V
CC
ismonitoredbyafilteredUVLOcircuit.WiththeV
CC
voltagepoweringupafterallotherpinshave
establishedconnection,theUVLOcircuitensuresthatthebackplaneandcarddataandclockbussesarenot
connecteduntilthetransientsassociatedwithliveinsertionhavesettled.Owingtotheirsmallcapacitance,the
SDAINandSCLINpinscauseminimaldisturbanceonthebackplanebusseswhentheymakecontactwiththe
connector.
Figure12.InsertingMultipleI/OCardsintoaLiveBackplaneUsingtheTCA4311inaCompactPCISystem
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Not Recommended For New Designs