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LTC4278 IEEE PoE Flyback Controller

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LTC4278 IEEE PoE Flyback Controller

Analog Devices’ controllers are designed for security systems, industrial controls, and dual-radio access points

Power by Linear™/Analog Devices’ LTC4278 is an integrated powered device (PD) controller and switching regulator intended for high power IEEE 802.3at and 802.3af applications. The input voltage range of the LTC4278 is specifically designed to support PD applications that include a low-voltage auxiliary power input such as a 12 V wall adapter. 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. This controller includes Linear Technology’s patented no-opto feedback topology to provide full IEEE 802.3 isolation without the need of an optoisolator circuit. A true soft-start function allows graceful ramp-up of all output voltages. This device is available in a 32-pin DFN package with operating temperature ranges of -40°C to +85°C. The LTC4278 was designed for security systems, industrial controls, and dual-radio access points.

  • 10 V to 57 V auxiliary power input
  • 25.5 W IEEE 802.3at compliant (Type 2) PD
  • 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
  • Robust 100 V 0.7 Ω (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
  • Power good indicators
  • PTZ security cameras
  • RFID readers
  • Industrial controls
  • VoIP phones with advanced display options
  • Dual-radio wireless access points