LT4294 - IEEE 802.3bt PD Interface Controller


  • IEEE 802.3af/at/bt (Draft 2.3) Powered Device (PD) Controller
  • Supports Up to 71W PDs
  • 5-Event Classification Sensing
  • Superior Surge Protection (100V Absolute Maximum)
  • Wide Junction Temperature Range (–40°C to 125°C)
  • Overtemperature Protection
  • Integrated Signature Resistor
  • External Hot Swap N-Channel MOSFET for Lowest Power Dissipation and Highest System Efficiency
  • Configurable Aux Power Support as Low as 9V
  • Easy Migration Between LTPoE++® PDs and IEEE 802.3bt PDs
  • Pin Compatible with LT4275A/B/C
  • Available in 10-Lead MSOP and 3mm × 3mm DFN Packages

Typical Application

LT4294 Typical Application


The LT®4294 is an IEEE 802.3af/at/bt (Draft 2.3)-compliant powered device (PD) interface controller. The T2P output indicates the number of classification events received during IEEE 802.3bt-compliant mutual identification and negotiation of available power.

The LT4294 utilizes an external, low RDS(ON) N-channel hot swap MOSFET and supports the LT4320/LT4321 ideal diode bridges, to extend the end-to-end power delivery efficiency and eliminate costly heat sinks. The LT4294 also includes a power good output, onboard signature resistor, undervoltage lockout, and thermal protection. Start-up inrush current is adjustable with an external capacitor. Auxiliary power override is supported as low as 9V with the AUX pin.

The LT4294 can be configured to support all possible 802.3bt, 802.3at and 802.3af power levels with external component changes. Pin-for-pin compatibility with the LT4275 family of PD Interface Controllers enables easy migration between LTPoE++ PDs and IEEE 802.3btcompliant PDs.


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

Part Number Package Code Temp Package
LT4294HDD#PBF 3x3 DFN-10 DD H 05-08-1699 Yes
LT4294HDD#TRPBF 3x3 DFN-10 DD H 05-08-1699 Yes
LT4294HMS#PBF MS-10 MS H 05-08-1661 Yes
LT4294HMS#TRPBF MS-10 MS H 05-08-1661 Yes
LT4294IDD#PBF 3x3 DFN-10 DD I 05-08-1699 Yes
LT4294IDD#TRPBF 3x3 DFN-10 DD I 05-08-1699 Yes
LT4294IMS#PBF MS-10 MS I 05-08-1661 Yes
LT4294IMS#TRPBF MS-10 MS I 05-08-1661 Yes

LT4294 Package Drawing
LT4294 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
LT4294HDD#PBF 3x3 DFN-10 H $3.34 $2.34 Yes
LT4294HDD#TRPBF 3x3 DFN-10 H $3.40 $2.40 Yes
LT4294HMS#PBF MS-10 H $3.34 $2.34 Yes
LT4294HMS#TRPBF MS-10 H $3.40 $2.40 Yes
LT4294IDD#PBF 3x3 DFN-10 I $2.79 $1.95 Yes
LT4294IDD#TRPBF 3x3 DFN-10 I $2.85 $2.01 Yes
LT4294IMS#PBF MS-10 I $2.79 $1.95 Yes
LT4294IMS#TRPBF MS-10 I $2.85 $2.01 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
DC2583A LT4294/LT4321 Demo Board | PoE++ (71W/37V-57V) PD and Ideal Diode Bridge $95.00
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  • High Power Wireless Data Systems
  • Outdoor Security Camera Equipment
  • Commercial and Public Information Displays
  • High Temperature Industrial Applications

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