It's designed for -48V distributed power systems and AdvancedTCA® equipment where two input sources must be combined with minimal forward drop and no reverse current flow. The part controls a 2:1 input-to-output ratio, meaning it selects between two -48V rails and passes the higher voltage to the load, blocking the lower one through the external FET.
The 700 ns delay time - OFF is the speed at which the controller can shut off the external N-channel MOSFET when it detects a reverse current condition. In a redundant -48V feed, a short on one rail must be isolated before the fault propagates to the healthy supply. That 700 ns window sets the upper bound on fault energy the MOSFET must absorb before the gate is pulled down — pick a FET with a gate charge low enough that the driver can pull it below threshold within that window. The 1.2 mA supply current is the controller's own draw, not the load current; the load passes through the external FET, so the 1.2 mA is a quiescent overhead that matters for standby efficiency in always-on telecom shelves.
It's an in-production part from Analog Devices, available through independent distribution channels. For smaller quantities, the Cut Tape (CT) option is also listed.