LTC4268-1

Features n Robust 35W PD Front End n IEEE 802.3af Compliant n Rugged 750mA Power MOSFET With Precision Dual Level Current Limit n High Performance Synchronous Flyback Controller n IEEE Isolation Obtained Without an Opto-Isolator n Adjustable Frequency from 50kHz to 250kHz n Tight Multi-Output Regulation With Load Compensation n Onboard 25k Signature Resistor n Programmable Classification Current to 75mA n Complete Thermal and Over-Current Protection n Available in Compact 32-Pin 7mm × 4mm DFN Package Applications n VoIP Phones With Advanced Display Options n Dual-Radio Wireless Access Points n PTZ Security Cameras n RFID Readers n Industrial Controls n Magnetic Card Readers n High Power PoE Systems LTC4268-1 High Power PD With Synchronous No-Opto Flyback Controller Description The LTC®4268-1 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 Linear Technology’s patented No-Opto feedback topology to provide full IEEE 802.3af isolatio...