The LTC4290 from Analog Devices is an 8-Port Power-over-Ethernet PSE Controller that has been designed for use in IEEE 802.3at Type 1 and Type 2 (high power)-compliant power-over-ethernet (PoE) systems. It requires an input voltage of 3 V to 3.6 V. This controller features a transformer-isolated communication protocol, replacing expensive opto-couplers and complex isolated 3.3V supplies, resulting in significant bill of materials (BOM) cost savings. It includes per-port 12-bit current monitoring ADCs, a DAC-programmable current limit, and the versatile fast shut-down of preselected ports.
This controller, leveraging low drain-source on-resistance external MOSFETs and 0.25 ohm sense resistors, ensures the chipset delivers the lowest-in-industry heat dissipation. It incorporates a proprietary dual-mode 4-point detection mechanism for PD discovery to provide robust immunity from false power delivery (PD) detection. The controller also supports midspan power sourcing equipments with 2-event classification and a 2-second backoff timer, and includes an I2C serial interface that is operable up to 1 MHz. It is available in a surface-mount package that measures 6 x 6 mm and is ideal for PoE PSE switches/routers and PoE PSE midspans applications.
