The LTC4278IDKD 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 LTC4278IDKD 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 LTC4278IDKD 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 LTC4278IDKD 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 LTC4278IDKD 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 LTC4278IDKD is available in a space saving 32-pin DFN package.
Feature
- 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 SynchronousFlyback 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
Applications
- VoIP Phones with Advanced Display Options
- Dual-Radio Wireless Access Points
- PTZ Security Cameras
- RFID Readers
- Industrial Controls
(Picture: Pinout)
