Features and Benefits

  • High Efficiency Over Wide Load Current Range
  • ±0.8% Output Voltage Accuracy
  • Dual N-Channel MOSFET Synchronous Drivers
  • Pulse Transformer Synchronization
  • Optocoupler Feedback Driver
  • Programmable Current Limit Protection
  • ±5% Margin Output Voltage Adjustment
  • Adjustable Overvoltage Fault Protection
  • Power Good Flag
  • Auxiliary 3.3V Logic Supply
  • Available in 16-Lead SSOP and SO Packages

Product Details

The LTC1698 is a precision secondary-side forward converter controller that synchronously drives external N-channel MOSFETs. It is designed for use with the LT3781 primary-side synchronous forward converter controller to create a completely isolated power supply. The LT3781 synchronizes the LTC1698 through a small pulse transformer and the LTC1698 drives a feedback optocoupler to close the feedback loop. Output accuracy of ±0.8% and high efficiency over a wide range of load currents are obtained.

The LTC1698 provides accurate secondary-side current limit using an external current sense resistor. The input voltage at the MARGIN pin provides ±5% output voltage adjustment. A power good flag and overvoltage input are provided to ensure proper power supply conditions. An auxiliary 3.3V logic supply is included that supplies up to 10mA of output current.


  • 48V Input Isolated DC/DC Converters
  • Isolated Telecommunication Power Systems
  • Distributed Power Step-Down Converters
  • Industrial Control Systems
  • Automotive and Heavy Equipment

Product Lifecycle icon-recommended Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

Evaluation Kits (3)

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.


Models for the following parts are available in LTspice:


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.

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The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.

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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.