Description
The PM8801 integrates a standard compliant 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/PoE+ interface incorporates all the functions required by the IEEE 802.3at including detection, classification, undervoltage lockout (UVLO) and inrush current limitation. The PM8801 specifically performs IEEE802.3at Layer1 hardware classification, providing an indication of type 2 PSE successful detection to the rest of the system. The PM8801 has been designed to work with power either from the Ethernet cable connection or from an external power source such as a wall adapter, ensuring prevalence of the auxiliary source with respect to the PoE interface. The DC/DC section of the PM8801 features a programmable oscillator frequency, an adjustable slope compensation, dual complementary lowside drivers with programmable delay time and internal temperature sensor. The PM8801 targets high-efficiency conversion at all load conditions supporting flyback, forward, forward active clamp and synchronous rectification. HTSSOP24

Features
■ IEEE 802.3at compliant PD interface
■ Works with power supplied from Ethernet LAN cables or from local auxiliary sources
■ Successful IEEE802.3at Layer1 classification indicator
■ Integrated 100 V, 0.45 Ω, 1 A hot-swap MOSFET
■ Accurate 140 mA typ. inrush current level
■ Programmable classification current
■ Sleep mode with LED indicator and Maintain Power Signature (MPS)
■ Precise DC current limit set at 640 mA typ.
■ Integrated high-voltage startup bias regulator

Applications
■ VoIP phones, WLAN AP
■ WiMAX CPEs
■ Security cameras
■ PoE/PoE+ Powered device appliances