Datasheet

8
LTC4301
4301fb
APPLICATIO S I FOR ATIO
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they make contact. CS is a short pin that is pulled up when
not connected. This is to ensure that the connection
between the backplane and the cards data and clock
busses is not enabled until the transients associated with
live insertion have settled.
Figure 4 shows the LTC4301 in a CompactPCI
TM
configu-
ration. The LTC4301 receives its V
CC
voltage from one of
the long “early power” pins. Because this power is not
switched, add a 5Ω to 10Ω resistor between V
CC
of the
LTC4301 and the connector V
CC
pin. Establishing early
power V
CC
ensures that the 1V precharge voltage is
present at SDAIN and SCLIN before they make contact.
The CS pin is driven by the CompactPCI’s BD_SEL# pin
using a short pin. This is to ensure that a connection is not
enabled until the transients associated with live insertion
have settled.
Figure 5 shows the LTC4301 in a PCI application where all
of the pins have the same length. In this case, an RC filter
circuit on the I/O card with a product of 10ms provides a
STAGGERED CONNECTOR
R13
10k
R12
10k
R14
10k
I/O PERIPHERAL CARD N
SDAIN
SCLIN
LTC4301
V
CC
GND
CARDN_SCL
CARDN_SDA
SDAOUT
SCLOUT
READY
SDAIN
SCLIN
V
CC
GND
SDAOUT
SCLOUT
READY
CS
SDAIN
SCLIN
V
CC
GND
SDAOUT
SCLOUT
READY
4301 F03
• • •
R9
10k
R8
10k
R10
10k
I/O PERIPHERAL CARD 2
LTC4301
CARD2_SCL
CARD2_SDA
STAGGERED CONNECTORSTAGGERED CONNECTOR
R5
10k
R4
10k
R6
10k
I/O PERIPHERAL CARD 1
LTC4301
CARD_SCL
CARD_SDA
R1
10k
V
CC
V
CC2
R2
10k
BACKPLANE
BACKPLANE
CONNECTOR
SDA
BD_SEL
SCL
0.01µF
R3
10k
5.1Ω
5.1Ω
5.1Ω
R7
10k
R11
10k
0.01µF
0.01µF
CS
CS
Figure 4. Inserting Multiple I/O Cards into a Live Backplane Using the LTC4301 in a CompactPCI System
CompactPCI is a trademark of the PCI Industrial Computer Manufacturers Group.