Alternative Parts


Features and Benefits

  • High-Speed Top and Bottom Gate Drivers for
  • 2-Switch Forward Converter
  • On-Chip Rectifier and Self-Starting Architecture
  • Eliminate Need for Separate Gate Drive Bias Supply
  • Wide Input Voltage Supply Range: 18V to 80V
  • Tolerant of 100V Input Voltage Transients
  • Linear Regulator Controller for Fast Start-Up
  • Precision UVLO with Adjustable Hysteresis
  • Overcurrent Protection
  • Volt-Second Limit Prevents Transformer Core Saturation
  • Voltage Feedforward for Fast Transient Response
  • Available in 16-Lead Narrow SSOP Package

Product Details

The LTC3705 is a controller for a 2-switch forward converter and includes on-chip bottom and top gate drivers that do not require external transformers. For secondary-side control, combine the LTC3705 with the LTC3706 PolyPhase® secondary-side synchronous forward controller to create a complete forward converter using a minimum of discrete parts. A proprietary scheme is used to multiplex gate drive signals across the isolation barrier through a tiny pulse transformer. The on-chip rectifier and the same pulse transformer provide gate drive bias power.

Alternatively, the LTC3705 can be used as a standalone voltage mode controller in a primary-side control architecture with optoisolator feedback. Voltage feedforward provides excellent line regulation and transient response.


  • Isolated 48V Telecommunication Systems
  • Internet Servers and Routers
  • Distributed Power Step-Down Converters
  • Automotive and Heavy Equipment

Product Lifecycle icon-not-recommended Not Recommended for New Designs

This designates products ADI does not recommend broadly for new designs.

Evaluation Kits (1)

Tools & Simulations


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Evaluation Boards

Pricing displayed is based on 1-piece.

Up to two boards can be purchased through To order more than two, please purchase through one of our listed distributors.

Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.