LTC4265

·IEEE 802.3af/at Powered Device (PD) Controller
·IEEE 802.3at 2-event Classifi cation Signaling
·Programmable Classifi cation Current
·Flexible Auxiliary Power Support Using SHDN Pin
·Rugged 100V Onboard MOSFET with 100mA Inrush Current Limit.
·Complementary Power Good Outputs
·Onboard Signature Resistor
·Comprehensive Thermal Protection
·Undervoltage and Overvoltage Lockout
·12-Lead, 4mm × 3mm DFN Package

· 802.11n Access Points
· High Power VoIP Video Phones
· RFID Reader Systems
· PTZ Security Cameras and Surveillance Equipment

GND Voltage ...................................................... 0.3V to 100V
V_OUT Voltage ...........................................0.3V to 100V (and GND)
V_OUT Pull-Up Current ........................................................1A
SHDN ............................................................. 0.3V to 100V
R_CLASS, Voltage .................................................... 0.3V to 7V
R_CLASS Current ..............................................................50mA
PWRGD Voltage (Note 4)
Low Impedance Source ....................................V_OUT 0.3V to V_OUT +11V
Pull-Up Current ..............................................................5mA
PWRGD, T2PSEVoltage ............................................... 0.3V to 100V
PWRGD, T2PSE Pull-Up Current ................................................10mA
Junction Temperature ........................................................ 125
Operating Ambient Temperature Range
LTC4265C ............................................................ 0 to 70
LTC4265I.......................................................... 40 to 85

The LTC4265 is a 3rd generation Powered Device (PD) Interface controller intended for IEEE 802.3at high power Power-over-Ethernet (PoE) applications up to 25.5W. By supporting 1-event and 2-event classifi cation signaling as defi ned by IEEE 802.3, the LTC4265 can be used in a wide range of product confi gurations. A 100V MOSFET isolates the DC/DC converter during detection and classifi cation, and provides 100mA inrush current for a smooth powerup transition. The LTC4265 also includes complementary power good outputs, an on-board signature resistor, undervoltage/overvoltage lockout and comprehensive thermal protection. All Linear Technology PD solutions include a shutdown pin with signature corrupt to provide flexible auxiliary power options.

The LTC4265 PD interface controller can be used along with a variety of DC/DC converter products to provide a complete, cost effective power solution for high power PD applications.

The LTC4265 is available in the space-saving low profile (4mm × 3mm) DFN package and is drop-in compatible with the LTC4264.