Rev. 1.2 1/15

Copyright © 2015 by Silicon Laboratories

Si3462-EVB

Si3462-EVB

1. Introduction

This document is intended to be used in conjunction with the Si3462 data sheet for designers interested in the

following:



An introduction to Power over Ethernet (PoE) and Power Sourcing Equipment (PSE) design considerations



Operation of the Si3462 PSE controller in the Si3462-EVB reference design



Configuration and operation of the Si3462-EVB

2. Overview of the Si3462 and Evaluation Board

The Si3462 is a single-port power management controller for IEEE 802.3at PoE/PoE+ compliant Power Sourcing

Equipment (PSE). The Si3462 operates directly from a 50 V (nominal) isolated input for PoE or 54 V (nominal)

isolated input for PoE+. The complete Si3462 reference design (i.e., the Si3462-EVB) also provides full

IEEE-compliant classification and detection as well as a robust disconnect algorithm. Intelligent protection circuitry

includes input under-voltage and over-voltage lockout (UVLO/OVLO), current limiting, and output short-circuit

protection.

The Si3462 is designed to operate completely independently of host processor control. A reset button and an

optional LED status signal are provided to indicate port status including detect, power good, and output fault event

information.

The Si3462 is pin-programmable to support:



No classification mode reduces bill of materials for 15.4 W operation and also for non-standard powered

devices that do not present a proper classification signature



Endpoint and midspan applications with support for either 10/100BASE-T or 10/100/1000BASE-T



All PoE/PoE+ classification power levels



Classification-based current limiting



Automatic or manual restart after various fault events are detected

Figure 1. Typical Application Circuit

Si3462

GND

DETA

+3.3 V

48 V

PSE

output

(to port

magnetics)

RST

VDD

Detect

&

Mark

ISENSE

GND

STATUS

CLSMODE

DC1

CLSMARK

VSENSE

DETECT

FAULT

PGOOD

DC2

+50 V

GND

+

_

+50 V

Classification

&

Gate drive

Optional 3.3 V regulator