Four-port PoE controllers offer four independent PSE ports

Analog Devices LTC4291/LTC4292 chipsets include isolated four-port PSE controllers designed for use in IEEE 802.3bt (PoE++) PoE systems. The controllers offer four independent PSE ports comprised of two channels each, ensuring fully compliant support for the next-generation of IEEE 802.3bt PDs. The LTC4291 series comprises a digital interface to the PSE host, while the LTC4292 series implements the high-voltage Ethernet power interface. The two ICs communicate using an Ethernet transformer. The transformer-isolated communication protocol replaces up to six optocouplers and a complex isolated 3.3V supply used in traditional designs. The devices operate seamlessly with compliant 802.3bt PD controllers. The devices PoE PSE controllers achieve extremely low heat dissipation by using low-RDS(ON) external MOSFETs and 0.15Ohm sense resistance per power channel. PD discovery is accomplished using a multi-point voltage and current detection mechanism, ensuring the best immunity from false PD detection. Using the PoE PSE controllers can deliver up to 71.3W of power to single-signature or dual-signature PDs.