High Power PD with Synchronous No-Opto Flyback Controller

The LTC4268-1 is an integrated Powered Device (PD) controller and switching regulator intended for IEEE 802.3af and high power PoE applications up to 35W. By including a precision dual current limit, the LTC4268-1 keeps inrush below IEEE 802.3af current limit levels to ensure interoperability success while enabling high power applications with a 750mA operational current limit.

The LTC4268-1 synchronous, current-mode, flyback controller generates multiple supply rails in a single conversion providing for the highest system efficiency while maintaining tight regulation across all outputs. The LTC4268-1 includes patented No-Opto feedback topology to provide full IEEE 802.3af isolation without the need of opto-isolator circuitry.

The oversized power path and high performance flyback controller of the LTC4268-1 combine to make the ultimate solution for power hungry PoE applications such as WAPs, PTZ security cameras, RFID readers and ultra-efficient 802.3af applications running near the 12.95W limit.

The LTC4268-1 is available in a space saving 32-pin DFN package.

Applications

* VoIP Phones with Advanced Display Options

* Dual-Radio Wireless Access Points

* PTZ Security Cameras

* RFID Readers

* Industrial Controls

* Magnetic Card Readers

* High Power PoE Systems

* Robust 35W PD Front End

* IEEE 802.3af Compliant

* Rugged 750mA Power MOSFET with Precision Dual Level Current Limit

* High Performance Synchronous Flyback Controller

* IEEE Isolation Obtained Without an Opto-Isolator

* Adjustable Frequency from 50kHz to 250kHz

* Tight Multi-Output Regulation with Load Compensation

* On-board 25k Signature Resistor

* Programmable Classification Current to 75mA

* Complete Thermal and Over-Current Protection

* Available in Compact 32-Pin 7mm × 4mm DFN Package