The ADM1172 is a hot swap controller that safely enables a printed circuit board to be removed and inserted to a live backplane. This is achieved using an external N-channel power MOSFET with a current control loop that monitors the load current through a sense resistor. An internal charge pump is used to enhance the gate of the N-channel FET. When an over-current condition is detected， the gate voltage of the FET is reduced to limit the current flowing through the sense resistor. During an overcurrent condition， the TIMER pin capacitor determines the amount of time the FET remains at a current limiting mode of operation until it is shut down. The ON （ON-CLR） pin is the enable input for the device and can be used to monitor the input supply voltage. The ADM1172 operates with a supply voltage ranging from 2.7 V to 16.5 V.

　　The ADM1172 also features a power-fail comparator. The voltage on the PFI pin is compared with an internal 0.6 V reference， and the output of this comparator is presented on the PFO pin. This device is available in two options： the ADM1172-1 with automatic retry for overcurrent fault and the ADM1172-2 with latch-off for an overcurrent fault. Toggling the ON （ON-CLR） pin resets a latched fault. The ADM1172 is packaged in an 8-lead TSOT.