WM5557 provides a complete interface for a powered device (PD) to comply with the IEEE® 802.3af/at standard in a power-over-Ethernet (PoE) system. WM5557 provides the PD with a detection signature, classification signature, and an integrated isolation power switch with inrush current control. During the inrush period, WM5557 limits the current to less than 180 mA before switching to the higher current limit (720 mA to 880 mA) when the isolation power MOSFET is fully enhanced. The device features an input UVLO with wide hysteresis and long deglitch time to compensate for twisted-pair cable resistive drop and to assure glitch-free transition during power-on/-off conditions. WM5557 can withstand up to 100V at the input.