LT4276 - LTPoE++/PoE+/PoE PD Forward/Flyback Controller
Features
- IEEE802.3af/at and LTPoE++™ 90W Powered Device (PD) with Forward/Flyback Controller
- LT4276A Supports All of the Following Standards:
- LTPoE++ 38.7W, 52.7W, 70W and 90W
- IEEE 802.3at 25.5W Compliant
- IEEE 802.3af up to 13W Compliant
- LT4276B is IEEE 802.3at/af Compliant
- LT4276C is IEEE 802.3af Compliant
- Superior Surge Protection (100V Absolute Maximum)
- Wide Junction Temperature Range (–40°C to 125°C)
- Auxiliary Power Support as Low as 9V
- No Opto-Isolator Required for Flyback Operation
- External Hot Swap™ N-Channel MOSFET for Lowest Power Dissipation and Highest System Efficiency
- >94% End-to-End Efficiency with LT4321 Ideal Bridge
- Available in a 28-Lead 4mm × 5mm QFN Package
Typical Application
Description
The LT®4276 is a pin-for-pin compatible family of IEEE 802.3 and LTPoE++ Powered Device (PD) controllers. It includes an isolated switching regulator controller capable of synchronous operation in both forward and flyback topologies with auxiliary power support.
The LT4276A employs the LTPoE++ classification scheme, receiving 38.7W, 52.7W, 70W or 90W of power at the PD RJ45 connector, and is backwards compatible with IEEE 802.3. The LT4276B is a fully 802.3at compliant, 25.5W Type 2 (PoE+) PD. The LT4276C is a fully 802.3af compliant, 13W Type 1 (PoE) PD.
The LT4276 supports both forward and flyback power supply topologies, configurable for a wide range of PoE applications. The flyback topology supports No-Opto feedback. Auxiliary input voltage can be accurately sensed with just a resistor divider connected to the AUX pin.
The LT4276 utilizes an external, low RDS(ON) N-channel MOSFET for the Hot Swap function, maximizing power delivery and efficiency, reducing heat dissipation, and easing the thermal design.
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 |
|---|---|---|---|---|---|
| LT4276AHUFD#PBF | 4x5 QFN-28 | UFD | H | 05-08-1712 | Yes |
| LT4276AHUFD#TRPBF | 4x5 QFN-28 | UFD | H | 05-08-1712 | Yes |
| LT4276AIUFD#PBF | 4x5 QFN-28 | UFD | I | 05-08-1712 | Yes |
| LT4276AIUFD#TRPBF | 4x5 QFN-28 | UFD | I | 05-08-1712 | Yes |
| LT4276BHUFD#PBF | 4x5 QFN-28 | UFD | H | 05-08-1712 | Yes |
| LT4276BHUFD#TRPBF | 4x5 QFN-28 | UFD | H | 05-08-1712 | Yes |
| LT4276BIUFD#PBF | 4x5 QFN-28 | UFD | I | 05-08-1712 | Yes |
| LT4276BIUFD#TRPBF | 4x5 QFN-28 | UFD | I | 05-08-1712 | Yes |
| LT4276CHUFD#PBF | 4x5 QFN-28 | UFD | H | 05-08-1712 | Yes |
| LT4276CHUFD#TRPBF | 4x5 QFN-28 | UFD | H | 05-08-1712 | Yes |
| LT4276CIUFD#PBF | 4x5 QFN-28 | UFD | I | 05-08-1712 | Yes |
| LT4276CIUFD#TRPBF | 4x5 QFN-28 | UFD | I | 05-08-1712 | Yes |
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 | |
|---|---|---|---|---|---|---|
| LT4276AHUFD#PBF | 4x5 QFN-28 | H | $5.31 | $3.72 | Yes | |
| LT4276AHUFD#TRPBF | 4x5 QFN-28 | H | $5.37 | $3.78 | Yes | |
| LT4276AIUFD#PBF | 4x5 QFN-28 | I | $4.43 | $3.10 | Yes | |
| LT4276AIUFD#TRPBF | 4x5 QFN-28 | I | $4.49 | $3.16 | Yes | |
| LT4276BHUFD#PBF | 4x5 QFN-28 | H | $4.46 | $3.12 | Yes | |
| LT4276BHUFD#TRPBF | 4x5 QFN-28 | H | $4.52 | $3.18 | Yes | |
| LT4276BIUFD#PBF | 4x5 QFN-28 | I | $3.71 | $2.60 | Yes | |
| LT4276BIUFD#TRPBF | 4x5 QFN-28 | I | $3.77 | $2.66 | Yes | |
| LT4276CHUFD#PBF | 4x5 QFN-28 | H | $3.60 | $2.52 | Yes | |
| LT4276CHUFD#TRPBF | 4x5 QFN-28 | H | $3.66 | $2.58 | Yes | |
| LT4276CIUFD#PBF | 4x5 QFN-28 | I | $3.21 | $2.25 | Yes | |
| LT4276CIUFD#TRPBF | 4x5 QFN-28 | I | $3.27 | $2.31 | Yes | |
| Buy Now • Request Samples | ||||||
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 |
|---|---|---|---|
| DC2046A-A | LT4276B/LT4321 Demo Board | PoE+ (25W, 3.3V/6.8A) PD with DC/DC and Ideal Diode Bridge | $95.00 | |
| DC2046A-B | LT4276B/LT4321 Demo Board | PoE+ (25W, 5V/4.7A) PD with DC/DC and Ideal Diode Bridge | $95.00 | |
| DC2046A-C | LT4276B/LT4321 Demo Board | PoE+ (25W, 12V/1.9A) PD with DC/DC and Ideal Diode Bridge | $95.00 | |
| DC2046A-D | LT4276B/LT4321 Demo Board | PoE+(25W, 24V/1A) PD with DC/DC and Ideal Diode Bridge | $95.00 | |
| DC2046A-E | LT4276A/LT4321 Demo Board | LTPoE++ (38.7W, 5V/7A) PD with DC/DC and Ideal Diode Bridge | $95.00 | |
| DC2046A-F | LT4276C/LT4321 Demo Board | PoE (13W, 5V/2.3A) PD with DC/DC and Ideal Diode Bridge | $95.00 | |
| DC2047A-A | LT4276B/LT4321 Demo Board | PoE+ (25W, 12V/1.9A) PD with DC/DC, Ideal Diode Bridge and 9V-57V AUX | $95.00 | |
| DC2262A-A | LT4276A/LT4321 Demo Board | LTPoE++ (70W, 5V/13A) PD with DC/DC and Ideal Diode Bridge | $95.00 | |
| DC2262A-B | LT4276A/LT4321 Demo Board | LTPoE++ (90W, 12V/7A) PD with DC/DC and Ideal Diode Bridge | $95.00 | |
| Buy Now | |||
Companion Boards
| Part Number | Description | Price | Documentation |
|---|---|---|---|
| DC1814A-A | LTC4274A-1 Demo Board | LTPoE++ (38.7W) PSE | $100.00 | |
| DC1815A-A | LTC4266A-1 Demo Board | 4-Port 38.7W LTPoE++ PSE (req. DC590) | $200.00 | |
| Buy Now | |||
Applications
- High Power Wireless Data Systems
- Outdoor Security Camera Equipment
- Commercial and Public Information Displays
- High Temperature Applications
People Who Viewed This Product Also Viewed
- LT4275 - LTPoE++/PoE+/PoE PD Controller
- LT4321 - PoE Ideal Diode Bridge Controller
- LT4320/LT4320-1 - Ideal Diode Bridge Controller
- LT4363 - High Voltage Surge Stopper with Current Limit
- LT8705 - 80V VIN and VOUT Synchronous 4-Switch Buck- Boost DC/DC Controller
- LT3748 - 100V Isolated Flyback Controller
- LTC4020 - 55V Buck-Boost Multi-Chemistry Battery Charger
- LTC4364 - Surge Stopper with Ideal Diode
- LT3042 - 20V, 200mA, Ultralow Noise, Ultrahigh PSRR RF Linear Regulator
- LT8471 - Dual Multitopology DC/DC Converters with 2A Switches and Synchronization
Product Notifications
Please login to your MyLinear account for notifications of datasheet updates, new document releases and LTspice model announcements for your favorite products. If you do not have a MyLinear account you may Sign Up Now.
Forgot your password? Click here.
Need help? Email mylinear@linear.com with questions and comments.
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:
LT4276A
Technical Support
- For immediate technical assistance, contact your local sales office or distributor or call 1-800-4-LINEAR (US customers only) or 408-432-1900.
- For less urgent requests, please complete our Technical Support Request Form. Please allow 2-3 business days for reply.
