Linear Introduces Single-Port Power over Ethernet Controller for Powered Devices

Linear introduces the LTC4279, a single-port Power over Ethernet (PoE) controller for power-supply devices (PSE) that delivers up to 123W for applications requiring high power through CAT-5e cables. The need for higher power delivery comes from a wide range of applications, including LTE picocells, LED signage, security surveillance systems, home automation and machine vision systems. The highly versatile LTC4279 provides power to a wide range of powered devices (PDs). This includes all legacy (<13W), IEEE 802.3at Type 1 (13W) and Type 2 (25.5W) PDs, as well as Linear Technology's proprietary LTPoE++ (up to 90W) and custom (<123W) PDs. The device supports two-wire and 4-wire output topologies, as well as single and dual feature architectures. Resistor-adjustable power options make the LTC4279 easy to configure for multiple outlets, simplifying design and bill of materials.

The LTC4279 provides fully autonomous operation for a wide range of PSE applications, including endpoint and mid-span power injectors. A low power sense resistor and external MOSFET simplify the thermal design; the traditional PSE uses a higher RDS(ON) and less robust MOSFET. The discovery of PD is accomplished using a highly reliable 4-point detection mechanism to ensure best-in-class resistance to PD false detection. The LTC4279 provides a rich set of PD grading mechanisms for broad system compatibility. Robustness is enhanced with grading based current cutoff and limit thresholds, short circuit protection and ±80V cable surge protection.

The LTC4279 is available in an industrial temperature grade (–40°C to 85°C) in a RoHS-compliant 4mm x 5mm QFN-20 and SO-16 package. The LTC4279 is priced at $3.45 each in 1,000-piece quantities and is available for production. The LTC4279 combines with the LT4275 and LT4276 PD controllers to achieve an end-to-end design of up to 123W.

Relevant LTC42 series products

Author：Brittany Antonia （The author of article owns the copyright.）