
Power over Ethernet chip delivers 123W over CAT5e
The LTC4279 delivers power to a wide variety of powered devices (PDs) from LTE picocell base stations, LED signage and security monitoring systems to home automation and machine vision systems. It supports all legacy (<13W), IEEE 802.3at Type 1 (13W) and Type 2 (25.5W) PDs, Linear’s proprietary LTPoE++ (up to 90W), and custom (<123W) PDs. 2-pair and 4-pair output topologies as well as single-signature and dual-signature architectures. Resistor-adjustable power selection allows the LTC4279 to be easily configured for multiple sockets, simplifying design and bill of materials.
The LTC4279 provides fully autonomous operation for a wide variety of PSE applications, including endpoints and midspan power injectors. A low power 0.1Ω sense resistor and external MOSFET wth low RDS(ON) simplify thermal design as traditional PSEs use less robust MOSFETs with higher RDS(ON). PD discovery is accomplished using a high reliability 4-point detection mechanism that ensures best-in-class immunity from false PD detection. The LTC4279 provides a comprehensive set of PD classification mechanisms to enable wide system compatibility. Robustness is reinforced with classification-dependent current cutoff and limit thresholds, short-circuit protection and ±80V cable surge protection.
The LTC4279 is offered in the industrial temperature grade (–40°C to 85°C) and is available in RoHS-compliant 4mm x 5mm QFN-20 and SO-16 packages. The LTC4279 is priced starting at $3.45 each in 1,000-piece quantities and is now available in production quantities. The LTC4279, combined with the LT4275 and LT4276 PD controllers, enable up to 123W end-to-end design.
For more information see www.linear.com/product/LTC4279
