The LTC®4222 Hot Swap™ controller allows two powerpaths to be safely inserted and removed from a live backplane.Using external N-channel pass transistors, boardsupply voltages and inrush currents are ramped up at anadjustable rate. An I2C interface and onboard ADC allowsfor monitoring of current, voltage and fault status foreach channel.The device features adjustable, analog, foldback currentlimit circuits and a Soft-Start circuit that sets the dI/dt ofthe inrush currents. An I2C interface may confi gure thepart to latch off or automatically restart after the LTC4222detects a fault on either channel.The controller has additional features to interrupt the hostwhen a fault has occurred, notify when output power isgood, detect insertion of a load card and power-up eitherautomatically upon insertion or wait for an I2C commandto turn on.