The LTC4224 Dual Low Voltage Hot SwapTM controller allows a board to be safely inserted and removed from a live backplane. It controls two supplies with external Nchannel MOSFETs and operates with one supply as low as 1V provided the other supply is 2.7V or greater. The LTC4224 can ramp up the supplies in any order and at adjustable ramp rates. To minimize the number of external components and PCB area, the gate capacitor is optional, all timing delays are generated internally, and the ON pins have integrated pull-up currents.