LTC4267-3 - 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.

  • 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
Typical Application
  • IP Phone Power Management
  • Wireless Access Points
  • Security Cameras
  • Power over Ethernet

Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LTC4267CDHC-3#PBF5x3 DFN-16C$2.92$2.20
LTC4267CDHC-3#TRPBF5x3 DFN-16C$2.30
LTC4267IDHC-3#PBF5x3 DFN-16I$3.50$2.65
LTC4267IDHC-3#TRPBF5x3 DFN-16I$2.75
Demo Boards
Part NumberDescriptionPrice
DC1249ALTC4267-3 PD, 37-57V input, 3.3V@ 3A out$75.00
Reliability Data
Product Selector Card
Related Product
LTC4267-3 - Power over Ethernet IEEE 802.3af PD Interface with Integrated Switching Regulator
LTC4267-3 Package Drawing LTC4267-3
PoE Consortium Clause # 33 PD Conformance Report
PoE Consortium Interoperability Report - LTC4267
R413 Reliability Data
PoE PD Controllers
Power over Ethernet Solutions
LTC4267-3 Footprints and Symbols