Features and Benefits

  • Supports Self-Starting Secondary-Side Control
  • Direct Flux Limit Guarantees No Saturation
  • Active Clamp Drive with Delay Adjustment
  • On-Chip Bridge Rectifier Eliminates Need for Separate Gate Drive Bias Supply
  • Wide Input Supply Range: 8V and Up (Limited Only by External Components)
  • Linear Regulator Controller for Fast Start-Up
  • High Speed Gate Drivers
  • Precision UVLO with Adjustable Hysteresis
  • Overcurrent Protection
  • Overtemperature Protection
  • Adjustable Start-Up Frequency and Soft-Start
  • Tiny 16-Lead MSOP Package

Product Details

The LTC3765 is a start-up controller and gate driver for use in a self-starting secondary-side control forward converter. When combined with the LTC3766 secondary-side synchronous forward controller, a complete isolated power supply is created using a minimum of discrete parts. A proprietary scheme is used to multiplex gate drive signals and bias power across the isolation barrier through a small pulse transformer. The LTC3765 contains an onchip bridge rectifier that extracts gate drive bias power from this pulse transformer, eliminating the need for a separate bias supply. A precision undervoltage lockout circuit and linear regulator controller ensure a quick and well-controlled start-up.

The LTC3765 includes an active clamp output for driving an external PMOS, as well as an adjustable delay to optimize efficiency. The active clamp architecture reduces voltage stress on the main power switch, and provides the highest possible efficiency. Overcurrent protection and the Direct Flux Limit guarantee no transformer saturation without compromising transient response.


  • Isolated Battery Chargers
  • Isolated 48V Telecommunication Systems
  • Servers and Embedded Computing
  • Automotive and Heavy Equipment

Product Lifecycle icon-recommended Recommended for New Designs

This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.

Evaluation Kits (5)

Tools & Simulations


LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.

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Product Recommendations

LTC3765 Companion Parts

Recommended Related Parts

Design Resources

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.

PCN-PDN Information

Sample & Buy

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Evaluation Boards

Pricing displayed is based on 1-piece.

Up to two boards can be purchased through Analog.com. 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.