Features and Benefits

  • Drives External Power MOSFET
  • Supply Voltage Range: 4.5V to 20V
  • Flyback Voltage Limited Only by External Components
  • Senses Output Voltage Directly from Primary Side Winding—No Optoisolator Required
  • Moderate Accuracy Regulation Without User Trims
  • Regulation Maintained Well into Discontinuous Mode
  • Switching Frequency from 50kHz to 250kHz with External Capacitor
  • Available in 16-Pin GN and SO Packages
  • Optional Load Compensation
  • Optional Undervoltage Lockout
  • External ISENSE Resistor
  • Shutdown Feature Reduces IQ to 50µA Typ

Product Details

The LT1737 is a monolithic switching regulator controller specifically designed for the isolated flyback topology. It drives the gate of an external MOSFET and is generally powered from a DC supply voltage. Output voltage feedback information may be supplied by a variety of methods including a third transformer winding, the primary winding or even direct DC feedback (see Applications Information). Its gate drive capability, coupled with a suitable external MOSFET and other power path components, can deliver load power up to tens of Watts.

The LT1737 has a number of features not found on other isolated flyback controller ICs presently available. By utilizing current mode switching techniques, it provides excellent AC and DC line regulation. Its unique control circuitry can maintain regulation well into discontinuous mode in most applications. Optional load compensation circuitry allows for improved load regulation. An optional undervoltage lockout pin halts operation when the application input voltage is too low. An optional external capacitor implements a soft-start function.


  • Isolated Flyback Switching Regulators
  • Medical Instruments
  • Instrumentation Power Supplies

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 (1)

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:


Product Recommendations

LT1737 Companion Parts

Recommended µModule Regulator

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

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Evaluation Boards

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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.