industry news
Subscribe Now

Isolated Power Factor Corrected Offline Regulator Needs No Opto

MILPITAS, CA – December 5, 2011 – Linear Technology Corporation announces the LT3798, an isolated flyback controller with single stage active power factor correction (PFC). A power factor of greater than 0.97 is accomplished by actively modulating the input current, eliminating the need for an extra switching power stage and associated components. In addition, no opto-isolator or signal transformer is required for feedback since the output voltage is sensed from the primary-side flyback signal.

A LT3798-based design easily complies with the IEC61000-3-2 Harmonic Current Emissions specification. Efficiencies greater than 86% can be achieved with output power levels up to 100W. The device’s input voltage range is dependent on the choice of external components and it can operate over a 90VAC to 277VAC range, and can easily be scaled higher or lower. Furthermore, the LT3798 can be designed into high input voltage DC applications, making it well suited for industrial, EV/EHV automotive, mining and medical applications. The LT3798 utilizes critical conduction mode operation, enabling the use of a smaller transformer compared to continuous conduction mode designs, further reducing the solution size.

The LT3798 is available in a thermally enhanced 16-pin MSOP package. The LT3798E and LT3798I versions operate from -40°C to 125°C. The LT3798H is tested and guaranteed to operate from a -40°C to 150°C operating junction temperature. 1,000-piece pricing starts at $2.25 each. All are available from stock. For more information, visit www.linear.com/product/LT3798 

Summary of Features: LT3798 

  • Active PFC Eliminates an Extra Power Stage
  • VIN & VOUT Limited Only by External Components, VIN >400VAC Possible
  • No Opto-Coupler Required
  • Better than ±5% Overall Regulation
  • High Efficiency
  • Low Harmonic Content
  • Low Component Count Results in Small Solution Size
  • Thermally Enhanced 16-Lead MSOP Package

About Linear Technology  

Linear Technology Corporation, a member of the S&P 500, has been designing, manufacturing and marketing a broad line of high performance analog integrated circuits for major companies worldwide for three decades. The Company’s products provide an essential bridge between our analog world and the digital electronics in communications, networking, industrial, automotive, computer, medical, instrumentation, consumer, and military and aerospace systems. Linear Technology produces power management, data conversion, signal conditioning, RF and interface ICs, and µModuleÒ subsystems.

Leave a Reply

featured blogs
Apr 24, 2026
A thought experiment in curiosity, confusion, and cosmic consequences....

featured paper

Want early design analysis without simulation?

Sponsored by Siemens Digital Industries Software

Traditional verification methods are failing today's complex IC designs, which require a proactive, early-stage analysis approach. A shift-left methodology addresses IP block integration challenges and the limitations of traditional simulation and ERC tools. Insight Analyzer detects hard-to-find leakage issues across power domains, enabling early analysis without full simulation. Identify inefficiencies earlier to reduce rework, improve reliability, and enhance power performance.

Click to read more!

featured chalk talk

Analog Output, Isolated Current, & Voltage Sensing Using Isolation Amplifiers
Sponsored by Mouser Electronics and Vishay
In this episode of Chalk Talk, Simon Goodwin from Vishay and Amelia Dalton chat about analog output, and isolated current and voltage sensing using isolation amplifiers. Simon and Amelia also explore the fundamental principles of current and voltage sensing and the variety of voltage and current sensing solutions offered by Vishay that can get your next design up and running in no time.
Apr 27, 2026
6,804 views