What the 802.3af PSE controller does on the board
The MAX5922AEUI+ is a single-channel Power Sourcing Equipment (PSE) controller that delivers up to 15.4 W per port per IEEE 802.3af — the original PoE standard that powers IP cameras, VoIP phones, and wireless access points over a single Ethernet cable. It integrates the switching FET and current-sense resistor internally, so the BOM stays tight — no external MOSFET or sense resistor to size and route. The 32 V to 60 V supply range covers the 48 V nominal PoE rail with headroom for cable drop and transient events on the midspan or switch backplane.
Active lifecycle and compliance posture
RoHS3 compliant (2011/65/EU + 2015/863), with no exemptions that complicate EU market entry.
Quiescent supply current is 1 mA typical — negligible in a multi-port switch but worth noting for battery-backed or energy-harvesting PSE applications where every milliwatt counts.