PCA9512AD,112

The PCA9512AD,112 is a hot swappable I?C Bus and SMBus Buffer allows I/O card insertion into a live backplane without corruption of the data and clock buses and includes two dedicated supply voltage pins to provide level shifting between 3.3 and 5V systems while maintaining the best noise margin for each voltage level. Either pin may be powered with supply voltages ranging from 2.7 to 5.5V with no constraints on which supply voltage is higher. Control circuitry prevents the backplane from being connected to the card until a stop bit or bus idle occurs on the backplane without bus contention on the card. When the connection is made, it provides bidirectional buffering, keeping the backplane and card capacitances isolated. The rise time accelerator circuitry allows the use of weaker DC pull-up currents while still meeting rise time requirements. The PCA9512A incorporates a digital input pin that enables and disables the rise time accelerators on all four SDAn and SCLn pins.