LTC4279 Series

Single Port PoE/PoE+/LTPoE++ PSE Controller

Catalog

Single Port PoE/PoE+/LTPoE++ PSE Controller

Part	Mounting Type	Operating Temperature [Max]	Operating Temperature [Min]	Auxiliary Sense	Number of Channels	Supplier Device Package	Internal Switch(s)	Current - Supply	Type	Power - Max [Max]	Package / Case	Package / Case [x]	Package / Case [y]	Voltage - Supply [Min]	Voltage - Supply [Max]	Standards
Analog Devices LTC4279IS#PBF	Surface Mount	85 °C	-40 °C		1	16-SO		1.7 mA	Controller (PSE)	90 W	16-SOIC	0.154 in	3.9 mm	45 V	57 V	802.3af 802.3at LTPoE++
Analog Devices LTC4279IUFD#PBF	Surface Mount	85 °C	-40 °C		1	20-QFN (4x5)		1.7 mA	Controller (PSE)	90 W	20-WFQFN Exposed Pad			45 V	57 V	802.3af 802.3at LTPoE++

Catalog

Single Port PoE/PoE+/LTPoE++ PSE Controller

Key Features

• Compliant with IEEE 802.3at Type 1 and 2

• Supports LTPoE++®Up to 90W

• Supports Dual-Signature PDs

• Fully Autonomous Operation without Microcontroller

• Very Low Power Dissipation

• 0.1Ω Sense Resistance

• Low RDS(ON)External MOSFET

• Very High Reliability 4-Point PD Detection

• 2-Point Forced Voltage and Forced Current

• Robust Short-Circuit Protection

• Cable Surge Protected ±80V OUT pin

• Classification Dependent ICUTand ILIMCurrent Thresholds

• Supports 2-Pair and 4-Pair Output Power

• UltraPWR Mode Supports Custom PDs up to 123W

• Pin-Selectable Detection Backoff Timer for Midspans

• Pin Programmable Legacy PD Detection

• Pin Programmable Maximum Power Mode

• Status LED Pin

• Available in 20-Pin QFN and 16-Pin SO Packages

Description

The LTC4279 is an autonomous single port power sourcing equipment (PSE) controller designed for use in IEEE 802.3at Type 1, Type 2 and LTPoE++ compliant Power over Ethernet (PoE) systems. The LTC4279 provides fully autonomous IEEE 802.3 and LTPoE++ compliant operation without a microcontroller. The LTC4279 simplifies PSE implementation, requiring only a single supply and a small number of passive support components.The LTC4279 delivers lowest-in-industry heat dissipation by utilizing a low-RDS(ON)external MOSFET and a 0.1Ω sense resistor, eliminating the need for expensive heat sinks and increasing efficiency.PD discovery uses a proprietary dual-mode 4-point detection mechanism ensuring excellent immunity from false PD detection. Midspan PSEs are supported with physical layer classification and a 2.5 second backoff timer.Legacy and custom PDs are supported with pin-selectable LEGACY and UltraPWR modes. LEGACY mode detects and powers pre-IEEE specification PDs. UltraPWR mode aggressively turns on and powers custom PDs requiring high inrush and/or operational currents.ApplicationsPoE PSE Endpoints (Switch/Router)PoE Midspan Power InjectorsPower ForwardersFemto CellsSecurity Systems