Isolated 4-Port 802.3bt PoE++ PSE controller delivers up to 71.3W

Analog Devices has launched the Power by Linear LTC4291/LTC4292 isolated 4-port power sourcing equipment (PSE) controller chipset for use in IEEE 802.3bt (PoE++) Power over Ethernet (PoE) systems.

The LTC4291/LTC4292 provides 4 independent PSE ports comprised of 2 channels each, ensuring fully compliant support for the next generation of IEEE 802.3bt powered devices (PDs).

The LTC4291 includes a digital interface to the PSE host, while the LTC4292 implements the high voltage Ethernet power interface. The two ICs intercommunicate using an Ethernet transformer.The transformer-isolated communication protocol replaces up to six expensive opto-couplers and a complex isolated 3.3V supply used in traditional designs, resulting in significant BOM cost savings and a more robust and easy to manufacture design.

The LTC4291/LTC4292 chipset operates seamlessly with compliant 802.3bt PD controllers, the LT4294 or LT4295, forming complete end-to-end PoE++, PoE+ and PoE solutions.Up to 71.3W of power can be delivered to single-signature or dual-signature PDs.

PD discovery is accomplished using a multipoint voltage and current detection mechanism, ensuring the best immunity from false PD detection.Advanced power management includes Autoclass support, prioritised fast shutdown, 14-bit per-port power and current readback, 8-bit programmable power limits and 7-bit programmable overload current limits.

Systems can be updated with field-upgradable firmware.

A 1MHz I2C interface allows a host controller to digitally configure the chipset or query port status. Power management “C” demonstration libraries are also available to reduce NRE and improve time to market.

The LTC4291/LTC4292 chipset is offered in the industrial temperature range.The LTC4291 digital controller is in a RoHS-compliant 24-pin 4mm x 4mm QFN package, while the LTC4292 analogue controller is in a 40-pin 6mm x 6mm QFN package.The LTC4291/LTC4292 is Analog Devices’ first 802.3bt PSE controller and provides an upgrade path from the popular LTC4266 4-port 802.3at PSE controller.

Author
Neil Tyler