The ADM1070 is a negative voltage hot swap controller that allows a board to be safely inserted and removed from a live 48 V backplane. The part achieves this by providing robust current limiting, protection against transient and nontransient short circuits and overvoltage and undervoltage conditions. The ADM1070 typically operates from a negative voltage of up to 80 V and can tolerate transient voltages of up to 200 V. In-rush current is limited to a programmable value by controlling the gate drive of an external N-channel FET. The current limit can be controlled by the choice of the sense resistor, RSENSE. Added control of the in-rush current is provided by an on-chip timer that uses pulsewidth modulation to allow the maximum current to flow for only 3% of the time. An autorestart occurs after a current limit timeout. After seven successive autorestarts, the fault will be latched and the part goes into shutdown with the result that the external FET is disabled until the power is reset.