The LTC4266AIUHF-4#PBF is a quad Power Sourcing Equipment (PSE) Controller capable of delivering up to 90W of LTPoE++ power to a compatible LTPoE++ powered device (PD). A proprietary detection/classification scheme allows mutual identification between LTPoE++ PSE and LTPoE++ PD while remaining compatible and interoperable with existing type 1 (13W) and type 2 (25.5W) PDs. The LTC4266A feature set is a superset of the popular LTC4266. It features low RON external MOSFETs and 0.25R sense resistors which are especially important at the LTPoE++ current levels to maintain the lowest possible heat dissipation. An advanced power management features include, 14-bit current monitoring ADCs, DAC-programmable current limit and versatile quick shutdown of preselected ports. Advanced power management host software is available under a no-cost license. PD discovery uses a proprietary dual-mode 4-point detection mechanism ensuring excellent immunity from false PD detection.