-48 V Full Feature Hot Swap Controller
The ADM1073 is a full-feature, negative voltage, hot swap controller that allows boards to be safely inserted and removed from a live −48 V backplane. The part provides precise and robust current limiting, and protection against both transient and nontransient short circuits in overvoltage and undervoltage conditions. The ADM1073 can operate from a negative voltage of −18 V to −80 V and can tolerate transient voltages of up to −200 V.
Inrush current is limited to a programmable value by control-ling the gate drive of an external N-channel FET. The maximum current limit is set by the choice of the sense resistor, RSENSE.
A built-in soft start function allows control of the inrush current profile by an external capacitor on the soft start (SS) pin.
An external capacitor on the TIMER pin determines the time for which the FET gate is controlled to be high when maximum inrush current flows. The ADM1073 employs a limited consec-utive retry scheme, whereby, if the load capacitance is not fully charged within one attempt, the FET gate is pulled low and retries after a cooling period.