The LTC4245 Hot Swap™ 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 on-board 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. The controller has additional features to interrupt the host when a fault has occurred, notify when output power is good, detect insertion of a load card and power-up in either the on or off state. Applications * Live Board Insertion * CompactPCI, CompactPCI Express, CompactTCA, PCI Express Systems * Allows Safe Insertion into Live CompactPCI™ or PCI Express™ Backplane * 8-Bit ADC Monitors Current and Voltage * I2C™/SMBus Interface * dI/dt Controlled Soft Start * Simultaneous or Sequenced Turn-On * ±20V Absolute Maximum Rating for ±12V Supplies * No External Gate Capacitor Required * Dual-Level Circuit Breaker and Current Limit * Bus Precharge Output * Power Good Input with Timeout * Optional Latch-off or Autoretry After Faults * Alerts Host After Faults * Integrated LOCALPCIRST# Logic * 36-Pin SSOP and 38-Pin (5mm × 7mm) QFN Packages