Evaluates: MAX5992A

MAX5992B

MAX5992A Evaluation Kit

General Description

The MAX5992A/B evaluation kit (EV kit) is a fully assem-

bled and tested surface-mount circuit board featuring

powered device (PD) interface controller IC, which pro

vides PD detection signature, PD classification signature,

inrush current control, undervoltage lockout (UVLO),

and active FET-bridge driver. The EV kit is a compact

and low-cost design used in power-over-Ethernet (PoE)

applications requiring DC power from an Ethernet

network port for PDs, such as fiber-to-the-femotocell/

picocell/microcell, fiber-to-the-home/fiber-to-the-building

(FTTH/FTTB), IP phones, wireless access nodes, and

security cameras.

The EV kit features a 2x2P PD or multi-PD redundancy

configuration using the ICs. The 2x2P powers a galvani-

cally isolated 100W, 250kHz switching-frequency, active-

clamped, synchronous-rectified forward DC-DC converter

using the MAX5974D. The device circuit achieves high

efficiency by using a forward DC-DC converter topology.

The surface-mount transformer provides up to +1500V

galvanic isolation for the output. The EV kit output voltage

is configured for +12V and provides up to 8.4A load current.

Note: In the multi-PD redundancy mode, the total output

power must be reduced to 50W, which is limited by the

LAN transformer on board. Its port current must be limited

to 1.2A per 2 pair.

The EV kit circuit receives its power from IEEE 802.3af/

at-compliant power-sourcing equipment (PSE). The PSE

provides the required -44V to -57V DC power over a

twisted-pair Ethernet network cable to the EV kit’s RJ45

connectors. The EV kit features an active FET bridge for

separating the DC power provided by an end-span or

mid-span Ethernet system.

Features

● IEEE 802.3af/at-Compliant PD Interface Circuit

● -39V to -57V Startup Input Voltage Range

● Active FET Bridge

● Demonstrates 2x2P PD and Multi-PD Redundancy

Configurations

● Demonstrates an Isolated 100W Active-Clamped,

Synchronous-Rectified Forward DC-DC Converter

● Isolated +12V Output at 8.4A

● PD Detection and Configurable Classification

Signatures

● Internal UVLO at +38.6V

● Evaluates End Span and Midspan Ethernet Systems

● Proven PCB Layout

● Fully Assembled and Tested

319-100383; Rev 1; 6/19

Ordering Information appears at end of data sheet.

Warning: The EV kit is designed to operate with high voltages. Dangerous voltages are present on this EV kit and on equipment

connected to it. Users who power up this EV kit, or power the sources connected to it, must be careful to follow safety procedures

appropriately to work with high-voltage electrical equipment.

Under severe fault or failure conditions, this EV kit may dissipate large amounts of power, which could result in the mechanical

ejection of a component or of component debris at high velocity. Operate this kit with care to avoid possible personal injury.

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