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Overview
Features and Benefits
- 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
Product Details
The LT4276 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.
Applications
- High Power Wireless Data Systems
- Outdoor Security Camera Equipment
- Commercial and Public Information Displays
- High Temperature Applications
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Recommended for New Designs
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
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