STMicroelectronics PM8800 series PoE Controllers

The PM8800 series from STMicroelectronics is an integrated IEEE 802.3af compliant PoE-PD interface and PWM controller with support of external source. The PM8800A integrates a standard power over Ethernet (PoE) interface and a current mode PWM controller to simplify the design of the power supply sections of all powered devices. The PoE interface incorporates all the functions required by the IEEE 802.3af including detection, classification, under-voltage lockout (UVLO) and in-rush current limitation. PM8800A specifically targets PD with extended power requirement with respect to the limit imposed by the 802.3af standard, embedding a hot-swap MOSFET capable of sustaining twice the current of the 802.3af standard with a programmable DC current limit. The integrated switching regulator has been designed to work with power either form the Ethernet cable connection or from an external power source such as AC adapter. The DC-DC section of the PM8800A features a programmable oscillator frequency, soft-start, slope compensation and embeds a voltage output error amplifier allowing use in both isolated and non isolated configuration.