Features

• 25.5W IEEE 802.3at Compliant (Type 2) PD
• Integrated State-of-the-Art Synchronous Flyback
  Controller
  – Isolated Power Supply Efficiency >92%
  – 88% Efficiency Including Diode Bridge and
• Hot Swap™ FET
• Flexible Integrated Auxiliary Power Support
• Superior EMI Performance
• Robust 100V 0.7Ω (Typ) Integrated Hot Swap MOSFET
• IEEE 802.3at High Power Available Indicator
• Integrated Signature Resistor and Programmable Class Current
• Undervoltage, Overvoltage and Thermal Protection
• Short-Circuit Protection with Auto-Restart
• Programmable Soft-Start and Switching Frequency
• Complementary Power Good Indicators
• Thermally Enhanced 7mm × 4mm DFN Package

Typical Application

Description

The LTC4269-1 is an integrated Powered Device (PD) controller and switching regulator intended for high power IEEE 802.3at and 802.3af applications. The LTC4269-1 is targeted for high efficiency, single and multioutput applications from 10W to 25W. By supporting both 1-event and 2-event classifications, as defined by the IEEE, the LTC4269-1 can be used in a wide range of product configurations.

The LTC4269-1 synchronous, current mode, flyback controller generates multiple supply rails in a single conversion step providing for the highest system efficiency while maintaining tight regulation across all outputs. The LTC4269-1 includes Linear Technology’s patented No-Opto feedback topology to provide full IEEE 802.3 isolation without the need of an opto-isolator circuit. A true soft-start function allows graceful ramp-up of all output voltages.

All Linear Technology PD solutions include a shutdown pin to provide flexible auxiliary power options. The LTC4269-1 can accommodate adaptor voltages from 18V to 60V and supports both PoE or aux dominance options. The LTC4269-1 is available in a space saving 32-pin DFN package.