90 W PD controller for 802.3bt designs
It also supports legacy 802.3af (PoE) and 802.3at (PoE+) standards, making it a drop-in for designs that need to scale power delivery as the infrastructure upgrades. This is an external-switch controller — there is no internal MOSFET, so the designer selects the switching FET to match the power stage's current and thermal requirements. The 60 V supply rating sets the absolute maximum for the input rail, which covers the typical 48 V PoE bus with margin for transients.
Because the MAX5996CATE+ has no internal switch, the bill of materials includes an external N-channel MOSFET and its gate-drive passives. This gives the designer freedom to choose a FET with the right Rds(on) and gate charge for the target efficiency, but it also adds a layout-critical loop from the controller's gate drive pin to the FET gate and back through the source sense. Keep that loop short and wide to avoid ringing at the switching node. The controller draws 1.2 mA supply current, which is the quiescent overhead for the housekeeping supply — the actual input current depends on the load power and the external FET's efficiency.