PCA9511 pdf datasheet (Hot swa

The PCA9511 is a are hot swappable I2C-bus and SMBus buffer
that allows I/O card insertion into a live backplane without corrupting
the data and clock buses. Control circuitry prevents the backplane
from being connected to the card until a STOP command or bus idle
occurs on the backplane without bus contention on the card. When
the connection is made, the PCA9511 provides bidirectional
buffering, keeping the backplane and card capacitances isolated.
The PCA9511 rise time accelerator circuitry allows the use of
weaker DC pull-up currents while still meeting rise time
requirements to prevent interference when there are multiple
devices in the same system. The PCA9511 incorporates a digital
ENABLE input pin, which enables the device when asserted HIGH
and forces the device into a low current mode when asserted LOW,
and an open-drain READY output pin, which indicates that the
backplane and card sides are connected together (HIGH) or not
(LOW).
During insertion, the PCA9511 SDA and SCL lines are precharged
to 1 V to minimize the current required to charge the parasitic
capacitance of the chip.
The dynamic offset design of the PCA9510/11/12/13/14 I/O drivers
allow them to be connected to another PCA9510/11/12/13/14 device
in series or in parallel and to the A side of the PCA9517. The
PCA9510/11/12/13/14 can not connect to the static offset I/Os used
on the PCA9515/15A/16/16A/17 B side and PCA9518.
APPLICATION
? cPCI, VME, AdvancedTCA cards and other multi-point backplane
cards that are required to be inserted or removed from an
operating system.