What the -48V supply range means for the board
The MAX5949AESA+ is a single-channel hot swap controller designed for -48V telecom and datacom backplanes. Its supply range spans -80V to -20V, covering the nominal -48V rail plus the transients and dips common on a floating battery plant. The controller draws 700 µA from the negative rail, a quiescent load that stays well under the standby budget of a line card. It does not integrate the series pass FET — that is an external N-channel MOSFET the designer selects based on the load current and thermal budget.
Programmable fault handling and auto-retry
The part supports programmable overvoltage (OVP), undervoltage (UVLO), circuit breaker threshold, and fault timeout. The fault response can be set to latched shutdown, auto-retry, or a timed circuit-breaker cycle — the mode is selected by the external resistor network on the TIMER and UV/OV pins.