LTC4291/LTC4292 4-Port PoE PSE Controllers Analog Devices Inc. LTC4291/LTC®4292 chipsets include isolated 4-port power sourcing equipment (PSE) controllers designed for use in IEEE 802.3bt (PoE++) Power over Ethernet (PoE) systems. The LTC4291/LTC4292 Controllers offer four independent PSE ports comprised of two channels each, ensuring fully compliant support for the next generation of IEEE 802.3bt powered devices (PDs). The LTC4291 series includes a digital interface to the PSE host, while the Analog Devices 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.