N+1 ORing controller for -48V telecom backplanes
The LTC4355HMS#TRPBF: It handles two input supplies feeding one output (2:1 ratio), making it the core of a diode-OR replacement in -48V distributed power systems and AdvancedTCA® equipment.
300 ns turn-off and 2 mA supply current
The 300 ns turn-off delay is the critical parameter here — when an input supply fails or shorts, the controller must disconnect the failing rail before the output droops below the hold-up voltage of the downstream converters. A slower part risks a bus collapse in a -48V system where the holdup capacitance is sized for milliseconds, not microseconds. Quiescent supply current is 2 mA, a reasonable overhead for a redundant power controller that stays active continuously. The part does not integrate the power FETs internally (Internal Switch(s): No), so the designer selects external N-channel MOSFETs sized to the load current and the worst-case fault energy.
Package and footprint — 16-MSOP
Surface-mount assembly with standard reflow profiles applies.
It is ROHS3 compliant.