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 control-ling 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 themaximum 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.