Interface controller extends range for IEEE 802.3bt compliance
Believed to be the first next-generation IEEE-compliant products to be released on the market, the LT4295 IEEE 802.3bt powered device interface controller is designed for applications requiring up to 71W of delivered power.
The next PoE standard – IEEE 802.3bt – enables manufacturers to go beyond the 25.5W allocated by the IEEE 802.3at standard. The new standard, also known as PoE++ or 4PPoE, increases the power budget, while supporting 10 GbE (10GBASE-T) and maintaining backward compatibility with older IEEE equipment.
The LT4295 is IEEE 802.3bt (Draft 2.0) -compliant and supports newly introduced features, including all additional power device classes (5, 6, 7 and 8), additional power device types (Type 3 and Type 4), and five-event classification.
The single-signature 802.3bt controller integrates an isolated switching regulator controller, capable of synchronous operation in both high efficiency forward and no-opto flyback topologies with auxiliary power support. This high level of integration simplifies front end designs by reducing component count and board space, claims the company. Unlike traditional controllers that integrate the power MOSFET, this controller controls an external MOSFET to “significantly” reduce overall heat dissipation and maximise power efficiency. This is particularly important at 802.3bt’s higher power levels. An external MOSFET architecture allows users to size the MOSFET to the application’s requirements; standard LT4295-based implementations routinely select 30mOhm RDS(ON) MOSFETs.
The controller is offered in industrial and automotive grades, supporting operating temperature ranges from -40 to +85 degree C and -40 to +125 degree C, respectively.