APPLICATION NOTE 6161

PoE Power Injector

By: Brian Rosario and Phill Leyva

Abstract: Many Power over Ethernet (PoE) applications require 25.5W or greater, Class 5 operation over a single port. The MAX5971A and MAX5971B PSE controllers with integrated MOSFET deliver up to 40W to a single port using endpoint or midspan modes. This design idea details a unique configuration for obtaining greater than 25.5W, and up to 80W, using two MAX5971A or MAX5971B controllers with integrated MOSFET and sense resistor.