LTC4278 Series

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

Catalog

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

Part	Number of Channels	Operating Temperature [Max]	Operating Temperature [Min]	Supplier Device Package	Package / Case	Mounting Type	Standards	Type	Voltage - Supply [Max]	Voltage - Supply [Min]	Current - Supply [Max]	Power - Max [Max]
Analog Devices LTC4278CDKD#PBF	1	70 °C	0 °C	32-DFN (7x4)	32-WFDFN Exposed Pad	Surface Mount	802.3af (PoE) 802.3at (PoE+)	Controller (PD) DC/DC	60 V	37.2 V	1.35 mA	25.5 W
Analog Devices LTC4278CDKD#TRPBF	1	70 °C	0 °C	32-DFN (7x4)	32-WFDFN Exposed Pad	Surface Mount	802.3af (PoE) 802.3at (PoE+)	Controller (PD) DC/DC	60 V	37.2 V	1.35 mA	25.5 W
Analog Devices LTC4278IDKD#PBF	1	85 °C	-40 °C	32-DFN (7x4)	32-WFDFN Exposed Pad	Surface Mount	802.3af (PoE) 802.3at (PoE+)	Controller (PD) DC/DC	60 V	37.2 V	1.35 mA	25.5 W
Analog Devices LTC4278CDKD	1	70 °C	0 °C	32-DFN (7x4)	32-WFDFN Exposed Pad	Surface Mount	802.3af (PoE) 802.3at (PoE+)	Controller (PD) DC/DC	60 V	37.2 V	1.35 mA	25.5 W
Analog Devices LTC4278CDKD-1	1	70 °C	0 °C	32-DFN (7x4)	32-WFDFN Exposed Pad	Surface Mount	802.3af (PoE) 802.3at (PoE+)	Controller (PD) DC/DC	60 V	37.2 V	1.35 mA	25.5 W

Catalog

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

Key Features

• 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

Description

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.ApplicationsVoIP Phones with Advanced Display OptionsDual-Radio Wireless Access PointsPTZ Security CamerasRFID ReadersIndustrial Controls