Power sourcing equipment controller chipset delivers up to 71.3W

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

The LTC4291/LTC4292 provides four independent PSE ports comprising two channels each, which are said to ensure 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 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, says the company.

The LTC4291/LTC4292 chipset operates 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 and there are robust 80V pins.

PD discovery is accomplished using a multipoint voltage and current detection mechanism, which is said to ensure 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 an 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.

http://www.analog.com/poe