PMP11107.2, Class 3 Dual Output Isolated Flyback Converter for PoE Applications Reference Design. This converter is used for Class 3 PoE applications that require 3.3V/1A and 5V/1A outputs. The dual output flyback converter with synchronous rectifiers provides excellent efficiency and small size for PoE applications, such as an IP phone. The TPS23753A contains both the PoE powered device and the PWM controller functions