LTC4278
PRODUCTIONIEEE 802.3at PD with Synchronous No-Opto Flyback Controller and 12V Aux Support
- Part Models
- 4
- 1ku List Price
- Starting From $3.44
Overview
- 25.5W IEEE 802.3at Compliant (Type 2) PD
- 10V to 57V Auxiliary Power Input
- Shutdown Pin for Flexible Auxiliary Power Support
- Integrated State-of-the-Art No-Opto Synchronous Flyback Controller
- – Isolated Power Supply Efficiency >92%
- – 88% Efficiency Including Diode Bridge and Hot Swap™ FET
- Superior EMI Performance
- Robust 100V 0.7Ω (Typ) Integrated Hot Swap MOSFET
- IEEE 802.3 at High Power Available Indicator
- Integrated Signature Resistor and Programmable Class Current
- Undervoltage, Overvoltage and Thermal Protection
- Short-Circuit Protection with Auto-Restart
- Programmable Soft-Start and Switching Frequency
- Complementary Power Good Indicators
- Thermally Enhanced 7mm × 4mm DFN Package
The LTC4278 is an integrated Powered Device (PD) controller and switching regulator intended for high power IEEE 802.3at and 802.3af applications. With a wide input voltage range, the LTC4278 is specifically designed to support PD applications that include a low-voltage auxiliary power input such as a 12V wall adaptor. The inclusion of a shutdown pin provides simple implementation of both PoE and auxiliary dominate applications. In addition, the LTC4278 supports both 1-event and 2-event classifications as defined by the IEEE, thereby allowing the use in a wide range of product configurations.
The LTC4278 synchronous, current mode, flyback controller generates multiple supply rails in a single conversion step providing for the highest system efficiency while maintaining tight regulation across all outputs. The LTC4278 includes Linear Technology’s patented No-Opto feedback topology to provide full IEEE 802.3 isolation without the need of an opto-isolator circuit. A true soft-start function allows graceful ramp-up of all output voltages.
The LTC4278 is available in a space saving 32-pin DFN package.
Applications
- VoIP Phones with Advanced Display Options
- Dual-Radio Wireless Access Points
- PTZ Security Cameras
- RFID Readers
- Industrial Controls
Documentation
Data Sheet 1
User Guide 1
Video 1
Product Selector Card 3
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal. View our quality and reliability program and certifications for more information.
| Part Model | Pin/Package Drawing | Documentation | CAD Symbols, Footprints, and 3D Models |
|---|---|---|---|
| LTC4278CDKD#PBF | 32-Lead DFN (7mm x 4mm w/ EP) | ||
| LTC4278CDKD#TRPBF | 32-Lead DFN (7mm x 4mm w/ EP) | ||
| LTC4278IDKD#PBF | 32-Lead DFN (7mm x 4mm w/ EP) | ||
| LTC4278IDKD#TRPBF | 32-Lead DFN (7mm x 4mm w/ EP) |
Software Resources
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Tools & Simulations
LTspice
Models for the following parts are available in LTspice:
- LTC4278
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
Evaluation Kits
LTC4278 IEEE802.3at PD Controller with 12V Auxiliary, VOUT = 5V, IOUT = 4.5A