The LTC4274CUHF is a single power sourcing equipment 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 LTC4274CUHF includes advanced power management features, including current and voltage readback and programmable ICUT and ILIM thresholds. Available C libraries simplify 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 LTC4274CUHF is available in a 5mm × 7mm QFN package that significantly reduces board space compared with competing solutions.
Feature
- 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
- 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 LTC4266 SW Compatible
- 1MHz I2C Compatible Serial Control Interface
- Midspan Backoff Timer
- Supports Proprietary Power Levels Above 25W
- Available in 38-Pin 5mm × 7mm QFN Package
Applications
- PSE Switches/Routers
- PSE Midspans
(Picture: Pinout)
