The LTC4245 Hot SwapTM controller allows a board to be safely inserted and removed from a live backplane in multiple supply systems such as CompactPCI and PCI Express. Using four external N-channel pass transistors, the board supply voltages can be ramped up at an adjustable rate and in any desired sequence. An I2C interface and onboard ADC allow monitoring of board current, voltage and fault status for each supply. The device features adjustable dI/dt controlled soft start and foldback limited inrush current. A dual-level timed circuit breaker and fast current limit protect each supply against overcurrent faults. A power good input with timeout allows a downstream supply monitor to disconnect the board supplies. The device can be configured to function without a 12V supply or with an extra 3.3V supply instead of a 5V supply.