What this -48V hot swap controller does on the backplane
The Maxim MAX5920BESA+ is a single-channel hot swap controller designed for -48V telecom power distribution. It manages inrush current during card insertion and removal, preventing backplane glitches and connector damage. The part does not contain an internal MOSFET — it drives an external series pass FET, giving the designer control over the power device selection for the load current. Supply range spans -80V to -20V, covering the -48V nominal rail with margin for transients and battery backup excursions. The 700 µA supply current keeps the quiescent draw negligible on the backplane. Programmable protection features include circuit breaker, current limit, overvoltage protection (OVP), and undervoltage lockout (UVLO). A fault timeout and latched fault response, combined with thermal limit, give the system a defined failure mode rather than an indefinite hiccup.
Industrial temperature grade and deployment environment
Rated for -40°C to 85°C operating temperature, the MAX5920BESA+ suits outdoor telecom cabinets, base-station shelters, and industrial -48V distribution panels where ambient temperature swings are routine. The 8-SOIC footprint (0.154" body width, 3.90 mm) is a common surface-mount package for backplane mezzanine cards and line-card controllers.
Lifecycle and sourcing reality
ROHS3 compliant.