1. General description
The PCA9511A is a hot swappable I
2
C-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 PCA9511A provides bidirectional buffering, keeping the
backplane and card capacitances isolated.
The PCA9511A rise time accelerator circuitry allows the use of weaker DC pull-up
currents while still meeting rise time requirements. The PCA9511A 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 PCA9511A SDA and SCL lines are precharged to 1 V to minimize
the current required to charge the parasitic capacitance of the chip.
2. Features
n Bidirectional buffer for SDA and SCL lines increases fan out and prevents SDA and
SCL corruption during live board insertion and removal from multipoint backplane
systems
n Compatible with I
2
C-bus Standard-mode, I
2
C-bus Fast-mode, and SMBus standards
n Built-in ∆V/∆t rise time accelerators on all SDA and SCL lines (0.6 V threshold)
requires the bus pull-up voltage and supply voltage (V
CC
) to be the same
n Active HIGH ENABLE input
n Active HIGH READY open-drain output
n High-impedance SDA and SCL pins for V
CC
=0V
n 1 V precharge on all SDA and SCL lines
n Supporting clock stretching and multiple master arbitration/synchronization
n Operating power supply voltage range: 2.7 V to 5.5 V
n 0 Hz to 400 kHz clock frequency
n ESD protection exceeds 2000 V HBM per JESD22-A114, 200 V MM per
JESD22-A115, and 1000 V CDM per JESD22-C101
n Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA
n Packages offered: SO8, TSSOP8 (MSOP8)
PCA9511A
Hot swappable I
2
C-bus and SMBus bus buffer
Rev. 04 — 19 August 2009 Product data sheet
