Linear Technology LTC4279IUFD#PBF

Description
The LTC4279 is a single-port Power Sourcing Equipment (PSE) controller for IEEE 802.3at Type 1, Type 2, and LTPOE compliant Power over Ethernet (PoE) systems. It operates autonomously without a microcontroller, simplifying PSE implementation. The LTC4279 features low power dissipation, a low-RDS(ON) external MOSFET, and a 0.102Ω sense resistor, eliminating the need for heatsinks and increasing efficiency.

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 - 0.102Ω sense resistance
Low Ros(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 ICUT and ILIM current 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

Applications
PoE PSE endpoints (switch/router)
PoE midspan power injectors
Power forwarders
Femto cells
Security systems