The LT4276 LTPoE++, PoE+, and PoE-compliant powered device (PD) interface controllers target applications requiring 2W to 90W of power. The device integrates a PD controller and an isolated switching regulator controller, capable of synchronous operation in both forward and flyback topologies with auxiliary power support. Unlike traditional PD controllers that integrate the power MOSFET, the LT4276 controls an external MOSFET to reduce overall PD heat dissipation and maximize power efficiency. This approach allows users to size the MOSFET to their application’s specific heating and efficiency requirements, enabling the use of MOSFETs with on resistances as low as 30 mΩ. A 100V rated input voltage means the LT4276 survives and protects PDs from the most common Ethernet line surges. The LT4276 is offered in industrial and extended temperature grades, supporting operating temperature ranges from -40°C to 85°C and -40°C to 125°C, respectively, and is available in small RoHS-compliant 28-lead 4 mm x 5 mm QFN packages. The LT4276 is priced starting at $2.25 each/1,000-piece quantities and is available in production quantities. The LT4276 provides an upgrade path from the company’s existing PD products, including the LT4275 LTPoE++ PD controller. The LT4276 can also be used with the LT4321 ideal diode bridge controller to maximize available power and reduce heat dissipation in PDs. For more information, visit http://www.linear.com/LTPoE++
Linear Technology Corp.