The LTC®4244/LTC4244-1 are Hot Swap™ controllers that allow a board to be safely inserted into and removed from a CompactPCI™ bus slot. External N-channel transistors control the 5V and 3.3V supplies while on-chip switches control the ±12V supplies. The 3.3V and 5V supplies can be ramped up at an adjustable rate. Electronic circuit breakers protect all four supplies against overcurrent faults. After the power-up cycle is complete, the TIMER pin capacitor serves as auxiliary VCC allowing the LTC4244/ LTC4244-1 to function without interruption in the presence of voltage spikes on the 12VIN supply. The PWRGD output indicates when all four supplies are within tolerance. The OFF/ON pin is used to cycle 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 combined on-chip with HEALTHY# in order to generate LOCAL_PCI_RST#.