Power over Ethernet IEEE 802.3af PD Interface with Integrated 300kHz Switching Regulator

The LTC4267-3 combines an IEEE 802.3af compliant Powered Device (PD) interface with a 300kHz current mode switching regulator, providing a complete power solution for PD applications. The LTC4267-3 integrates the 25k signature resistor, classification current source, thermal overload protection, signature disable and power good signal along with an undervoltage lockout optimized for use with the IEEE-required diode bridge. The LTC4267-3 provides an increased operational current limit, maximizing power available for class 3 applications.

The 300kHz current mode switching regulator provides higher output power or smaller external size compared to its lower frequency counterparts. The LTC4267-3 is designed for driving a 6V rated N-channel MOSFET and features programmable slope compensation, soft-start, and constant-frequency operation, minimizing noise even with light loads. The LTC4267-3 includes an onboard error amplifier and voltage reference allowing use in both isolated and nonisolated configurations.

The LTC4267-3 is available in a space saving, low profile 16-pin SSOP or DFN packages.

Applications

* IP Phone Power Management

* Wireless Access Points

* Security Cameras

* Power over Ethernet

* Complete Power Interface Port for IEEE 802®.3af Powered Device (PD)

* Onboard 100V, UVLO Switch

* Constant-Frequency 300kHz Operation

* Precision Dual Level Inrush Current Limit

* Integrated Current Mode Switching Regulator

* Onboard 25k Signature Resistor with Disable

* Programmable Classification Current (Class 0-4)

* Thermal Overload Protection

* Power Good Signal

* Integrated Error Amplifier and Voltage Reference

* Low Profile 16-Pin SSOP or DFN Packages