The TCA4311ADGKR is a hot-swappable I2C Bus Buffer that supports I/O card insertion into a live backplane without corruption of the data and clock busses. 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, this device provides bidirectional buffering, keeping the backplane and card capacitances isolated. During insertion, the SDA and SCL lines are pre-charged to 1V to minimize the current required to charge the parasitic capacitance of the chip. When the I2C bus is idle, the buffer can be put into shutdown mode by setting the EN pin low. When EN is high, the buffer resumes normal operation. It also includes an open drain READY output pin, which indicates that the backplane and card sides are connected together. The size of the pull-up resistors to the I/Os depends on the system, but each side of this buffer must have a pull-up resistor.
Supports bidirectional data transfer of I2C bus signals
SDA and SCL lines are buffered which increases fan-out
SDA and SCL input lines are isolated from outputs
Accommodates standard-mode and fast-mode I2C devices
Improved noise immunity
Applications include hot board insertion and bus extension
Low ICC chip disable of <1μA
READY open-drain output
Supports clock stretching, arbitration and synchronization
Powered-OFF high-impedance I2C-bus pins
Open-drain I2C pins
Latch-up performance exceeds 100mA per JESD 78, class II
(EN)
