The LTC1646 is a Hot SwapTM controller that allows a board to be safely inserted and removed from a live CompactPCI bus slot. Two external N-Channel transistors control the 3.3V and 5V supplies. The supplies can be ramped-up in current limit or a programmable rate. Electronic circuit breakers protect both supplies against overcurrent fault conditions. The PWRGD output indicates when all of the supply voltages are within tolerance. The OFF/ON pin is used to cycle the board power or reset the circuit breaker. The PRECHARGE output can be used to bias the bus I/O pins during card insertion and extraction. PCI_RST# is logically combined on-chip with HEALTHY# in order to generate LOCAL_PCI_RST# which can be used to reset the CPCI card logic if either of the supply voltages is not within tolerance.