LTC4278

PRODUCTION

IEEE 802.3at PD with Synchronous No-Opto Flyback Controller and 12V Aux Support

Data Sheet Product Selection Table

Part Models: 4
1ku List Price: Starting From $2.71

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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

Part Models: 4
1ku List Price: Starting From $2.71

Documentation

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)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC4278CDKD#TRPBF	32-Lead DFN (7mm x 4mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC4278IDKD#PBF	32-Lead DFN (7mm x 4mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC4278IDKD#TRPBF	32-Lead DFN (7mm x 4mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

Software Resources

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Hardware Ecosystem

Parts	Product Life Cycle	Description
Analog to Digital Converters (ADCs) 1
LTC2991	RECOMMENDED FOR NEW DESIGNS	Octal I²C Voltage, Current, and Temperature Monitor
Circuit Monitors 1
LT2940	PRODUCTION	Power and Current Monitor
Power-over-Ethernet (PoE) Controllers 1
LT4275	PRODUCTION	LTPoE++/PoE+/PoE PD Controller

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.