The LTC4266A 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 a 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. These PSE controllers feature low RON external MOSFETs and 0.25Ω sense resistors which are especially important at the LTPoE++ current levels to maintain the lowest possible heat dissipation.The LTC4266C targets fully automatic PSE systems powering Type 1 (up to 13W) PDs.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. The LTC4266 includes an I2C serial interface operable up to 1MHz.The LTC4266 is available in multiple power grades allowing delivered PD power of 13W, 25.5W, 38.7W, 52.7W, 70W and 90W. These controllers are available in a 38-lead 5mm × 7mm QFN package.ApplicationsLTPoE++ PSE Switches/RoutersLTPoE++ PSE MidspansIEEE 802.3at Type 1 PSE Switches/RoutersIEEE 802.3at Type 1 PSE Midspans