LTC4266 - Quad IEEE 802.3at Power Over Ethernet Controller


  • Four Independent PSE Channels
  • Compliant with IEEE 802.3at Type 1 and 2
  • 0.34Ω Total Channel Resistance
  • 130mW/Port at 600mA
  • Advanced Power Management
  • 8-Bit Programmable Current Limit (ILIM)
  • 7-Bit Programmable Overload Currents (ICUT)
  • Fast Shutdown of Preselected Ports
  • 14.5-Bit Port Current/Voltage Monitoring
  • 2-Event Classification
  • Very High Reliability 4-Point PD Detection
  • 2-Point Forced Voltage
  • 2-Point Forced Current
  • High Capacitance Legacy Device Detection
  • LTC4259A-1 and LTC4258 Pin and SW Compatible
  • 1MHz I2C Compatible Serial Control Interface
  • Midspan Backoff Timer
  • Supports Proprietary Power Levels Above 25W
  • Available in 38-Pin 5mm × 7mm QFN and 36-Pin SSOP Packages

Typical Application

LTC4266 Typical Application


The LTC®4266 is a quad PSE controller designed for use in IEEE 802.3 Type 1 and Type 2 (high power) compliant Power over Ethernet systems. External power MOSFETs enhance system reliability and minimize channel resistance, cutting power dissipation and eliminating the need for heatsinks even at Type 2 power levels. External power components also allow use at very high power levels while remaining otherwise compatible with the IEEE standard. 80V-rated port pins provide robust protection against external faults.

The LTC4266 includes advanced power management features, including current and voltage readback and programmable ICUT and ILIM thresholds. Available C libraries simplify power-management software development; an optional AUTO pin mode provides fully IEEE-compliant standalone operation with no software required. Proprietary 4-point PD detection circuitry minimizes false PD detection while supporting legacy phone operation. Midspan operation is supported with built-in 2-event classification and backoff timing. Host communication is via a 1MHz I2C serial interface.

The LTC4266 is available in a 5mm × 7mm QFN package that significantly reduces board space compared with competing solutions. A legacy-compatible 36-pin SSOP package is also available.


CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
LTC4266CGW#PBF SSOP-36 GW C 05-08-1642 (GW36) Yes
LTC4266CGW#TRPBF SSOP-36 GW C 05-08-1642 (GW36) Yes
LTC4266CUHF#PBF 5x7 QFN-38 UHF C 05-08-1701 Yes
LTC4266CUHF#TRPBF 5x7 QFN-38 UHF C 05-08-1701 Yes
LTC4266IGW#PBF SSOP-36 GW I 05-08-1642 (GW36) Yes
LTC4266IGW#TRPBF SSOP-36 GW I 05-08-1642 (GW36) Yes
LTC4266IUHF#PBF 5x7 QFN-38 UHF I 05-08-1701 Yes
LTC4266IUHF#TRPBF 5x7 QFN-38 UHF I 05-08-1701 Yes

LTC4266 Package Drawing
LTC4266 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
LTC4266CGW#PBF SSOP-36 C $7.14 $5.00 Yes
LTC4266CGW#TRPBF SSOP-36 C $5.06 Yes
LTC4266CUHF#PBF 5x7 QFN-38 C $7.14 $5.00 Yes
LTC4266CUHF#TRPBF 5x7 QFN-38 C $5.06 Yes
LTC4266IGW#PBF SSOP-36 I $7.86 $5.50 Yes
LTC4266IGW#TRPBF SSOP-36 I $5.56 Yes
LTC4266IUHF#PBF 5x7 QFN-38 I $7.86 $5.50 Yes
LTC4266IUHF#TRPBF 5x7 QFN-38 I $5.56 Yes
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* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Part Number Description Price Documentation
DC1366B LTC4266 Demo Board | 25.5W PoE+ 4-Port Midspan PSE (req. DC590) $200.00
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Companion Boards

Part Number Description Price Documentation
DC590B Isolated USB Serial Controller for Linear Technology QuikEval-Compatible Demo Boards $50.00
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Click here to view our complete list of demo boards


  • High Power PSE Switches/Routers
  • High Power PSE Midspans

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Design Tools

Linear Technology provides a variety of custom design simulation tools and device models to allow even novice designers to quickly and easily evaluate circuits using high performance switching regulators, amplifiers, data converters, filters and more. Please visit our Design Tools page to view and download:

  • LTspice - A powerful SPICE simulator, schematic capture and waveform viewer with enhancements and models for easing the simulation of switching regulators
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