LTC4267

Complete Power Interface Port for IEEE 802^® .3afPowered Device (PD)
Onboard 100V, 400mA UVLO Switch
Precision Dual Level Inrush Current Limit
Integrated Current Mode Switching Regulator
Onboard 25k Signature Resistor with Disable
Programmable Classifi cation Current (Class 0-4)
Thermal Overload Protection
Power Good Signal
Integrated Error Amplifi er and Voltage Reference
Low Profi le 16-Pin SSOP and 3mm  5mm DFN Packages

The LTC^® 4267 combines an IEEE 802.3af compliant Pow-ered Device (PD) interface with a current mode switching regulator, providing a complete power solution for PD applications. The LTC4267 integrates the 25k signature resistor, classifi cation current source, thermal overload pro-tection, signature disable and power good signal along with an undervoltage lockout optimized for use with the IEEE-required diode bridge. The precision dual level input current limit allows the LTC4267 to charge large load capacitors and interface with legacy PoE systems.

The current mode switching regulator LTC4267 is designed for driving a 6V rated N-channel MOSFET and features pro-grammable slope compensation, soft-start, and constant frequency operation, minimizing noise even with light loads. The LTC4267 includes an onboard error amplifi er and voltage reference allowing use in both isolated and nonisolated confi gurations.

The LTC4267 is available in space saving, low profi le 16-pin SSOP or DFN packages.