Si3460
IEEE 802.3af PSE INTERFACE AND DC-DC CONTROLLER
Features
Pin Assignments
ꢀ
ꢀ
ꢀ
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
ꢁ 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
Si3460
1
2
3
4
5
10
9
GATE
CTRL1
VDD
STATUS
ISENSE
8
GND
RST
ꢁ Operates directly from a +12 or
+15 V isolated supply
ꢁ dc-dc controller generates –48 V
7
ꢀ
CTRL2
250KHZ
VSENSE
DETA
6
PSE output for SELV compatibility ꢀ Extended operating range
with telephony interfaces (–40 to +85 °C)
ꢁ Supports up to 15.4 W maximum ꢀ 11-Pin Quad Flat No-Lead (QFN)
11-pin QFN (3x3 mm)
Top View—Pads on bottom of package
output power (Class 0)
ꢁ Tiny 3 x 3 mm PCB footprint;
Pb-free, RoHS-compliant
Applications
ꢀ IEEE 802.3af endpoints and ꢀ Set-top boxes
midspans
ꢀ Environment A and B PSEs
ꢀ FTTH media converters
ꢀ Cable modem and DSL
ꢀ Embedded PSEs
gateways
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.
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.