Preliminary Rev. 0.4 11/07

Copyright © 2007 by Silicon Laboratories

Si3460

This information applies to a product under development. Its characteristics and specifications are subject to change without notice.

Si3460

Features

Applications

Description

The Si3460 is a single-port –48 V power management controller for

IEEE 802.3af-compliant Power Sourcing Equipment (PSE). Designed

to minimize system cost and ease of implementation in embedded

PSE endpoint (switches) or midspan (power injector) applications, the

Si3460 operates directly from a 12 or 15 V input supply and integrates

a digital PWM-based dc-dc converter for generating the –48 V PSE

output supply. The IEEE-required Powered Device (PD) detection

feature uses a robust 3-point algorithm to avoid false detection events.

The Si3460's reference design kit also provides full IEEE-compliant

classification and PD disconnect. Intelligent protection circuitry

includes input undervoltage lockout (UVLO), current limiting, and

output short circuit protection. The Si3460 is designed to operate

completely independently of host processor control. An LED status

signal is provided to indicate the port status, including detect, power

good, and output fault event information for use within the host

system. The Si3460 is pin-programmable to support endpoint and

midspan applications, as well as each of the different classification

power levels specified by

the IEEE

802.3af

standard.

A

comprehensive reference design kit is available (Si3460-EVB),

including a complete schematic and BOM (Bill-of-Materials) for the dc-

dc converter and PSE functions.

IEEE 802.3af™ compliant PSE and

dc-dc controller

Autonomous operation requires no

host processor interface

Complete reference design

available, including Si3460 controller,

PSE firmware, and schematic:

Low-cost BOM with compact PCB

footprint

Operates directly from a +12 or

+15 V isolated supply

dc-dc controller generates –48 V

PSE output for SELV compatibility

with telephony interfaces

Supports up to 15.4 W maximum

output power (Class 0)

Robust 3-point detection

algorithm eliminates false

detection events

IEEE-compliant classification

IEEE-compliant disconnect

Inrush current control

Short-circuit output fault

protection

LED status signal (detect,

power good, output fault)

UNH Interoperability Test Lab test

report available

Extended operating range

(–40 to +85 °C)

11-Pin Quad Flat No-Lead (QFN)

Tiny 3 x 3 mm PCB footprint;

Pb-free, RoHS-compliant

IEEE 802.3af endpoints and

midspans

Environment A and B PSEs

Embedded PSEs

Set-top boxes

FTTH media converters

Cable modem and DSL

gateways

Pin Assignments

11-pin QFN (3x3 mm)

Top View—Pads on bottom of package

ISENSE

STATUS

VSENSE

RST

DETA

1

2

3

4

5

10

9

8

7

6

CTRL1

GATE

CTRL2

VDD

250KHZ

GND

Si3460