Power Over Ethernet, POE Controller, 57V/ 500uA, 40V UVLO Threshold, SOIC-8 - 

The TPS2378DDA is an IEEE 802.3at PoE High-power PD Interface with AUX control. The low 0.5Ω internal switch resistance, combined with the enhanced thermal dissipation enables this controller to continuously handle up to 0.85A. The TPS2378 features an auxiliary power detect (APD) input, providing priority for an external power adapter. It also features a 100V pass transistor, 140mA inrush current limiting, type-2 indication, auto-retry fault protection and an open-drain power-good output. It contains several protection features such as thermal shutdown, current limit foldback and a robust 100V internal switch. The APD pin is used in applications that may draw power either from the Ethernet cable or from an auxiliary power source.