Datasheet

7
LTC4301
4301fb
Live Insertion and Capacitance Buffering Application
Figures 3 illustrates applications of the LTC4301 with
different bus pull-up and V
CC
voltages, demonstrating its
ability to recognize and buffer bus data levels that are
above or below its V
CC
supply. All of these applications
take advantage of the LTC4301’s Hot Swap
TM
controlling,
capacitance buffering and precharge features. If the I/O
cards were plugged directly into the backplane without the
LTC4301 buffer, all of the backplane and card capaci-
tances would add directly together, making rise- and fall-
time requirements difficult to meet. Placing an LTC4301
APPLICATIO S I FOR ATIO
WUUU
on the edge of each card, however, isolates the card
capacitance from the backplane. For a given I/O card, the
LTC4301 drives the capacitance of everything on the card
and the backplane must drive only the capacitance of the
LTC4301, which is less than 10pF.
In most applications the LTC4301 will be used with a
staggered connector where V
CC
and GND will be long pins.
SDA and SCL are medium length pins to ensure that the
V
CC
and GND pins make contact first. This will allow the
precharge circuitry to be activated on SDA and SCL before
STAGGERED CONNECTOR
CS
SDAIN
SCLIN
V
CC
GND
SDAOUT
SCLOUT
READY
10k 10k
LTC4301
CARD_SCL
CARD_SDA
0.01µF
10k
10k10k
BACKPLANE
CONNECTOR
5V
3.3V
SDA
SCL
STAGGERED CONNECTOR
CS
SDAIN
SCLIN
V
CC
GND
SDAOUT
SCLOUT
READY
10k 10k
LTC4301
CARD_SCL
CARD_SDA
0.01µF
10k
10k10k
BACKPLANE
CONNECTOR
3.3V
5V
SDA
SCL
STAGGERED CONNECTOR
CS
SDAIN
SCLIN
V
CC
GND
SDAOUT
SCLOUT
READY
4301 F03
10k
2.5V
10k
LTC4301
CARD_SCL
CARD_SDA
0.01µF
10k
10k10k
BACKPLANE
CONNECTOR
CARD
CARD
CARD
3.3V
5V
SDA
SCL
Figure 3. Typical Supply Independent Applications
Hot Swap is a trademark of Linear Technology Corporation.