July 8, 2015 – Linear Technology Korea (CEO Hong Sa-gwak) announced the launch of the LT4276, an LTPoE++™, PoE+, and PoE-compliant PD (powered device) interface for applications requiring 2W to 90W of power. The LT4276 integrates a PD controller and isolated switching regulator controller, enabling synchronous operation in forward and flyback topologies with auxiliary power support capability. This integrated performance simplifies front-end PD design by reducing component count and board space, allowing the LT4276A (LTPoE++), LT4276B (PoE+), and LT4276C (PoE) to efficiently deliver power to PD loads using a single IC.

Linear Technology's LTPoE++ standard extends the power budget across four power levels (38.7W, 52.7W, 70W, 90W), expanding support for very high-power applications such as picocell base stations, traffic signals, and heated outdoor security cameras. Unlike traditional PD controllers that integrate only power MOSFETs, the LT4276 controls external MOSFETs to dramatically reduce total PD thermal dissipation and maximize power efficiency. This characteristic is particularly important at higher power levels. This novel approach allows users to size their designs to match the specific thermal and efficiency requirements of their applications. Consequently, MOSFETs with RDS(ON) as low as 30mΩ can be used as needed. The 100V rated input voltage means the LT4276 easily withstands the most common Ethernet line surges while protecting the PD.

The LT4276 is available in industrial and extended temperature grades, supporting operating temperature ranges of –40°C to 85°C and –40°C to 125°C respectively. It is available in a compact, RoHS-compliant 28-pin 4mm x 5mm QFN package. The LT4276 is priced at $2.25 per unit based on 1,000-unit quantity and is available in production volumes. The LT4276 provides an upgrade path from Linear Technology's existing PD products such as the LT4275 LTPoE++ PD controller and is fully compatible with Linear Technology's latest PSE controllers, including single-port LTC4274, 4-port LTC4266, 8-port LTC4290/71 chipset, and 12-port chipset LTC4270/71. The LT4276 can be used with the LT4321 ideal diode bridge controller to maximize available power in the PD and reduce thermal dissipation. For more information, refer to http://www.linear.com/LTPoE++.

90W PoE (Power over Ethernet) PD Interface Controller

Product Features: LT4276

• IEEE 802.3af/at & LTPoE++ 90W PD (Powered Device) with Forward/Flyback Controller

• Standards Supported by LT4276A

·LTPoE++™ 38.7W, 52.7W, 70W & 90W

·IEEE 802.3at 25.5W Compliant

·IEEE 802.3af Up to 13W Compliant

• LT4276B Complies with IEEE 802.3at/af

• LT4276C Complies with IEEE 802.3af

• Excellent Surge Protection (100V Absolute Maximum)

• Wide Junction Temperature Range (–40°C to 125°C)

• Low Auxiliary Power Support as Low as 9V

• No Optoisolator Required for Flyback Operation

Hot Swap™ N-Channel for Lowest Power Consumption & Maximum System Efficiency

• LT4321 Ideal Bridge Achieves Over 94% End-to-End Efficiency

• Available in 28-pin 4mm x 5mm QFN Package