SI3462-E01-GM

Rev. 1.0 11/11Copyright © 2011 by Silicon LaboratoriesSi3462Si3462S INGLE-P ORT IEEE 802.3 AT P OE/P OE PSE I NTERFACEFeaturesApplicationsDescriptionThe Si3462 is a single-port power management controller for IEEE 802.3at-compliant Power Sourcing Equipment (PSE). The Si3462 can be poweredfrom a 50 V input using a shunt regulator, or, to save power, it can be poweredfrom 50 V and 3.3 V power supplies. The IEEE-required Powered Device (PD)detection feature uses a robust 3-point algorithm to avoid false detectionevents. The Si3462's reference design kit also provides full IEEE-compliantclassification and PD disconnect. Intelligent protection circuitry includes inputunder-voltage lockout (UVLO), classification-based current limiting, and outputshort-circuit protection. The Si3462 is designed to operate completelyindependently of host processor control. An LED status signal is provided toindicate the port status, including detection, power good, and output faultevent information. The Si3462 is pin-programmable to support four availablepower levels, endpoint and mid-span applications, and auto-retry or restartafter disconnect functions. A comprehensive reference design kit is available(Si3462-EVB), including a complete schematic and bill of materials. TheSi3462 also features “no-classify” modes, for circumstances where detectionis desired but classification steps can be skipped. Example applicationsinclude dedicated, point-to-point connections for IP cameras, point-of-saleterminals,andwireless access pointswherethe applicationpowerrequirements are well understood. These modes allow elimination ofclassification-related components from the bill of materials. IEEE 802.3atTM compliant PSE Autonomous operation requires nohost processor interface Complete reference designavailable, including Si3462 controllerand schematic:Low-cost BOMCompact PCB footprintOperates directly from a 50 Visolated supplySupports up to 30 W maximumoutput power (Class 4)Robust 3-point detection algorithmeliminates false detection eventsIEEE-compliant disconnectInrush current controlShort-circuit output faultprotectionLED status signal (detect,power good, output fault) UNH Interoperability Test Labreport available Extended operating range(–40 to 85 °C) 11-Pin Quad Flat No-Lead (QFN)packageTiny 3x3 mm PCB footprint;RoHS-compliant No-classify modes force powerafter valid detectionEliminates 10 BOMcomponents IEEE 802.3at endpoints andmidspans Environment A and B PSEs Embedded PSEs Set-top boxes FTTH media converters Cable modem and DSL gatewaysPin Assignments11-pin QFN (3x3 mm)Top View—Pads on bottom of packageISENSESTATUSVSENSERSTDETA12345109876DC1CLSMARKDC2VDDCLSMODEGNDSi3462