Features and Benefits

  • IEEE 802.3af/at-Compliant PSE Circuit
  • Port Current Read-Out Through I²C Interface
  • High-Power Class 5 Mode Configurable Up to 40W
  • -32V to -60V Input Voltage Providing 1A
  • Ethernet Network Ports
    • RJ45 10/100/1000BASE-TX Ethernet Network Data Input Port
    • RJ45 10/100/1000BASE-TX Ethernet Network PSE Output Port
  • Demonstrates MAX5971B Internal Power Switch and Current Sensing
  • Demonstrates Standard and Legacy PD Detection and Classification
  • Configurable for Midspan or End-Point Mode
  • Configurable AC/DC Load-Removal Detection and Disconnect Monitoring
  • Convenient Voltage and Current Test Points
  • Demonstrates IC's Output-Port LED Status Indicators
  • Optically Isolated I²C-Compatible 2-Wire PC Interface
  • Reconfigurable for Stand-Alone Operation or with an External Microcontroller (Requires +3.3V, 35mA Supply)
  • Windows 2000-, Windows XP-, and Windows Vista (32-Bit)-Compatible Software
  • Proven PCB Layout
  • Fully Assembled and Tested

Product Details

The MAX5971B evaluation kit (EV kit) is a fully assembled and tested surface-mount PCB featuring an Ethernet single-port power-sourcing equipment (PSE) circuit for -54V supply rail systems. The IEEE® 802.3af/at-compliant MAX5971B PSE controller IC, in a 28-pin TQFN package, features an internal n-channel power MOSFET forming the main PSE circuit on the EV kit. The IC is used in single-port power-over-Ethernet (PoE) applications.

The EV kit provides optical isolation for the IC's I²C-compatible 2-wire interface. The isolated interface can connect to a PC's USB port through an on-board USB interface circuit. The EV kit can be reconfigured for interfacing to a user's stand-alone microcontroller for isolated or nonisolated operation. In stand-alone operation, the user must supply a separate +3.3V power supply capable of supplying 35mA. The EV kit requires a -32V to -60V power supply (-54V supply rail) capable of supplying 1A or more to the EV kit for powering the powered device (PD) through the 10/100/1000BASE-TX Ethernet network port. The EV kit demonstrates PD discovery, classification, current-limit control, and other functions of an IEEE 802.3af/at-compliant PSE.

The IC controls the -54V DC power to the Ethernet network port by sensing current through the port and controlling the IC's internal power MOSFET. Current is fed to a 1Gb x 1Gb MagJack® module Ethernet output port.

The EV kit demonstrates the full functionality of the IC, such as configurable operational modes, port current information through the I²C interface, high-power modes (programmable up to 40W), PD detection (including legacy PD detection), PD classification, overcurrent protection, current foldback, undervoltage/overvoltage protection, and AC-/DC-disconnect monitoring. All these features are configurable on the EV kit, with additional test points for voltage probing and current measurements provided. The EV kit can also be configured for midspan or end-point network operation. The EV kit software is Windows® 2000, Windows XP®, and Windows Vista® compatible, providing a user-friendly interface to demonstrate the IC features while providing access to each register at the bit level. The program is menu driven, offers a graphical user interface (GUI) with control buttons, and includes a macro engine for automated evaluation and testing of the IC at the system level. The program's macro output files can be automatically saved.

Order the EV kit for a complete PC-based evaluation of the IC. To evaluate the MAX5971A IC, order the MAX5971A EV kit.


  • Single-Port PSE End-Point Applications
  • Single-Port PSE Power Injectors (Midspan Applications)
  • Switches/Routers

Applicable Parts

Tools & Simulations

Software Development


Pricing displayed is based on 1-piece.

Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.