The PCA9513 and PCA9514 are hot swappable I2C and SMBus buffers 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, PCA9513, and PCA9514 provides bi-directional buffering, keeping the backplane and card capacitances isolated. Rise time accelerator circuitry allows the use of weaker DC pull-up currents while still meeting rise time requirements. The PCA9513 and PCA9514 incorporate 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). The PCA9513 supplies a 92 mA current source to SCLIN and SDAIN in lieu of using pull-up resistors for PICMG backplane applications. Including the current source in the device provides for a consistent RC time constant as cards are removed and inserted into the backplane. The current source is high-impedance whenever the pin voltage is greater than the part VCC. PCA9513 and PCA9514 rise time accelerator threshold is 0.8 V to provide improved noise margin over the PCA9510 and PCA9511. 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