The LTC4266 is a quad PSE controller designed for use in IEEE 802.3 Type 1 and Type 2 (high power) compliant Power over Ethernet systems. External power MOSFETs enhance system reliability and minimize channel resistance, cutting power dissipation and eliminating the need for heatsinks even at Type 2 power levels. External power components also allow use at very high power levels while remaining otherwise compatible with the IEEE standard. 80V-rated port pins provide robust protection against external faults. The LTC4266 includes advanced power management features, including current and voltage readback and programmable ICUT and ILIM thresholds. Available C libraries simplify power-management software development; an optional AUTO pin mode provides fully IEEE-compliant standalone operation with no software required. Proprietary 4-point PD detection circuitry minimizes false PD detection while supporting legacy phone operation. Midspan operation is supported with built-in 2-event classification and backoff timing. Host communication is via a 1MHz I2C serial interface. The LTC4266 is available in a 5mm × 7mm QFN package that significantly reduces board space compared with competing solutions. A legacy-compatible 36-pin SSOP package is also available. Applications * High Power PSE Switches/Routers * High Power PSE Midspans * Four Independent PSE Channels * Compliant with IEEE 802.3at Type 1 and 2 * 0.34Ω Total Channel Resistance * 130mW/Port at 600mA * Advanced Power Management * 8-Bit Programmable Current Limit (ILIM) * 7-Bit Programmable Overload Currents (ICUT) * Fast Shutdown of Preselected Ports * 14.5-Bit Port Current/Voltage Monitoring * 2-Event Classification * Very High Reliability 4-Point PD Detection * 2-Point Forced Voltage * 2-Point Forced Current * High Capacitance Legacy Device Detection * LTC4259A-1 and LTC4258 Pin and SW Compatible * 1MHz I2C Compatible Serial Control Interface * Midspan Backoff Timer * Supports Proprietary Power Levels Above 25W * Available in 38-Pin 5mm × 7mm QFN and 36-Pin SSOP Packages https://elecena.pl/product/862693/quad-ieee-802-3at-power-over-ethernet-controller 2009-06-30 https://elecena.pl/product/862693/quad-ieee-802-3at-power-over-ethernet-controller 2017-10-28 https://elecena.pl/product/862693/quad-ieee-802-3at-power-over-ethernet-controller 2025-01-18