The PM8803 from STMicroelectronics is an IEEE 802.3at-Compliant Power-Over-Ethernet Controller IC that has been designed to simplify the design of power supply sections of all powered devices. It requires an input voltage of 48 V and delivers an output power of 25.5 W. This controller IC includes a PWM controller, power-over-ethernet (PoE) interface manager, DC-DC conversion circuitry, gate controller, current and voltage sensors, MOSFETs, and protection capabilities. It incorporates all functions required by the IEEE 802.3at as well as detection, classification, under-voltage lockout (UVLO), and in-rush current limitation functionalities. This integrated controller can receive power either from an Ethernet LAN cable or from other external power sources such as a wall adapter, which ensures the priority of the auxiliary source over the PoE. It consists of a current mode pulse width modulator and offers a duty cycle of up to 80% with internal slope compensation.

This PoE controller also provides support for flyback, forward, forward active clamp, and flyback with synchronous rectification to support high-efficiency DC-DC conversion. It integrates under-voltage lockout (UVLO) and in-rush current limiters to prevent false triggers or over-current-related damages. This IC is available in a surface-mount package that measures 6.4 x 6.2 mm and is ideal for PoE/PoE+ powered device appliances, WiMAX CPEs, VoIP phones, security cameras, and WLAN (AP) applications.