Supply range and protection programmability
The MAX5921FESA+T: Operating from -80V down to -20V, this controller covers the standard -48V telecom bus with headroom for transients. The 700 µA supply current is the controller's own draw, not the load current — the part has no internal switch, so the pass FET is external and sized for the actual load. Programmable features include circuit breaker, current limit, overvoltage protection (OVP), and undervoltage lockout (UVLO), plus an auto-retry and fault timeout. That means you set the trip thresholds and retry behavior with external resistors — no firmware, just analog.
Thermal and board-fit note
The thermal limit feature protects the external FET, but the controller itself stays cool at 700 µA — no heatsinking needed on the SOIC.