DESCRIPTION
The LTC® 4266 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.

FEATURES
■ 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

APPLICATIONS
■ High Power PSE Switches/Routers
■ High Power PSE Midspans