Products, Materials + Tools | Feb 09, 2011

Linear's New Isolated Active PFC Off-Line LED Controller without Opto-Isolator is TRIAC Dimmable

Linear Technology announces the LT3799, an isolated LED controller with active PFC, specifically designed for driving LEDs from a universal input range of 90 VAC to 265 VAC. The LT3799 is optimized for LED applications requiring 4 W to over 100 W of LED power and also compatible with standard TRIAC in-wall dimmers. The controller's unique current sensing scheme delivers a well regulated current to the secondary side without using an opto-coupler.

• Isolated PFC LED Driver with Minimum Number of External Components
• TRIAC Dimmable
• VIN and VOUT Limited Only by External Components
• Active Power Factor Correction (Typical PFC > 0.97)
• Low Harmonic Content
• No Opto-Coupler Required
• Accurate Regulated LED Current (±5% Typical)
• Open LED and Shorted LED Protection
• Thermally Enhanced 16-lead MSOP Package

• Offline 4W to 100W+ LED Applications
• High DC VIN LED Applications

This not only reduces cost but also improves reliability. It's single stage PFC regulator design requires minimal external components. Additionally, it's thermally enhanced MSOP-16E package ensures a simple and compact solution footprint for off-line LED applications.

The LT3799 offers over 86% efficiency, eliminating the need for external heat sinking of the LED driver IC in most applications. Special internal circuitry provides active PFC of up to 0.977, easily meeting industrial Department of Energy (DOE) requirements while also complying with the IEC 61000-3-2 Class C Lighting Equipment Harmonics requirement.

The LT3799 can be used with a standard in-wall TRIAC dimmer without any visible flicker. Open and shorted LED protection ensures long-term reliability for a wide range of LED applications.

About Linear Technology:
Linear Technology Corporation, a manufacturer of high performance linear integrated circuits, was founded in 1981, became a public company in 1986 and joined the S&P 500 index of major public companies in 2000. Linear Technology products include high performance amplifiers, comparators, voltage references, monolithic filters, linear regulators, DC-DC converters, battery chargers, data converters, communications interface circuits, RF signal conditioning circuits, uModule™ products, and many other analog functions. Applications for Linear Technology’s high performance circuits include telecommunications, cellular telephones, networking products such as optical switches, notebook and desktop computers, computer peripherals, video/multimedia, industrial instrumentation, security monitoring devices, high-end consumer products such as digital cameras and MP3 players, complex medical devices, automotive electronics, factory automation, process control, and military and space systems. For more information, visit