**LTC4279IUFD#TRPBF: A High-Power PoE++ PD Interface Controller with Advanced Features**

The **LTC4279IUFD#TRPBF** from Analog Devices is a highly integrated **Power over Ethernet (PoE) Powered Device (PD) interface controller** designed to meet the demanding requirements of modern high-power applications. Compliant with the **IEEE 802.3bt PoE++ standard**, this controller is engineered to manage the complex power negotiation and delivery process for devices requiring up to 90W of power, making it an ideal solution for a wide array of equipment, from **access points and surveillance cameras to advanced telecommunications and industrial systems**.

A cornerstone of the LTC4279's architecture is its **advanced power management capability**. It features a robust **dual-signature interface**, which allows a single PD to present two independent power identities to the Power Sourcing Equipment (PSE). This enables flexible and redundant powering configurations, which are critical for high-availability systems. The IC incorporates a low-resistance external hot-swap MOSFET, which minimizes power loss and thermal dissipation, thereby enhancing overall system efficiency and reliability.

The device excels in its **automatic classification support**, which is vital for the IEEE 802.3bt standard. It can handle all four classes of single-signature PDs and both types of dual-signature PDs, ensuring optimal power allocation from the PSE. This sophisticated classification mechanism prevents overloading the PSE while guaranteeing that the PD receives the maximum power it is qualified for.

Furthermore, the LTC4279 integrates **comprehensive protection features** to safeguard both the PD and the PSE. These include **thermal shutdown**, inrush current limiting, undervoltage and overvoltage lockout, and a programmable power good indicator. Its ability to operate over a wide temperature range makes it suitable for harsh environments.

Housed in a compact 4mm x 5mm QFN package, the LTC4279 offers a high level of integration in a small footprint, simplifying board design and saving valuable space. Its high efficiency and advanced feature set make it a superior choice for designers pushing the limits of PoE technology.

**ICGOO**DFIND: The LTC4279IUFD#TRPBF stands out as a premier PoE++ PD interface controller, offering high-power handling, dual-signature support, and robust integrated protection, making it essential for next-generation powered devices.

**Keywords:** IEEE 802.3bt, Powered Device (PD), Power over Ethernet (PoE++), Dual-Signature, High-Power.