LTC4274 - Single PoE+ PSE Controller

Features

  • 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
  • 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 LTC4266 SW Compatible
  • 1MHz I2C Compatible Serial Control Interface
  • Midspan Backoff Timer
  • Supports Proprietary Power Levels Above 25W
  • Available in 38-Pin 5mm × 7mm QFN Package

Typical Application

LTC4274 Typical Application

Description

The LTC®4274 is a single power sourcing equipment 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 LTC4274 includes advanced power management features, including current and voltage readback and programmable ICUT and ILIM thresholds. Available C libraries simplify 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 LTC4274 is available in a 5mm × 7mm QFN package that significantly reduces board space compared with competing solutions.

Packaging

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
Drawing
RoHS
LTC4274CUHF#PBF 5x7 QFN-38 UHF C 05-08-1701 Yes
LTC4274CUHF#TRPBF 5x7 QFN-38 UHF C 05-08-1701 Yes
LTC4274IUHF#PBF 5x7 QFN-38 UHF I 05-08-1701 Yes
LTC4274IUHF#TRPBF 5x7 QFN-38 UHF I 05-08-1701 Yes


LTC4274 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
(1-99)
Price
(1k)*
RoHS
LTC4274CUHF#PBF 5x7 QFN-38 C $6.43 $4.50 Yes
LTC4274CUHF#TRPBF 5x7 QFN-38 C $4.56 Yes
LTC4274IUHF#PBF 5x7 QFN-38 I $7.07 $4.95 Yes
LTC4274IUHF#TRPBF 5x7 QFN-38 I $5.01 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
DC1567B LTC4274 Demo Board | IEEE802.3at Power Over Ethernet PSE $75.00
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Click here to view our complete list of demo boards

Applications

  • PSE Switches/Routers
  • PSE Midspans

Product Notifications

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Design Tools

LTspice

LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

Models for the following parts are available in LTspice:
LTC4274

Technical Support