LT3837 - Isolated No-Opto Synchronous Flyback Controller

The LT3837 is an isolated switching regulator controller designed for medium power flyback topologies. A typical application is 10W to 60W with the part powered from a DC supply.

The LT3837 is a current mode controller that regulates an output voltage based on sensing the secondary voltage via a transformer winding during flyback. This allows for tight output regulation without the use of an optoisolator, improving dynamic response and reliability. Synchronous rectification increases converter efficiency and improves output cross regulation in multiple output converters.

The LT3837 operates in forced continuous conduction mode which improves cross regulation in multiple winding applications. Switching frequency is user programmable and can be externally synchronized. The part also has load compensation, undervoltage lockout and soft-start circuitry.

The LT3837 is available in a thermally enhanced 16-pin TSSOP package.

Features
  • Senses Output Voltage Directly from Primary Side Winding—No Optoisolator Required
  • Synchronous Driver for High Efficiency
  • Supply Voltage Range 4.5V to 20V
  • Accurate Regulation Without User Trims
  • Programmable Switching Frequency from 50kHz to 250kHz
  • Synchronizable
  • Load Compensation
  • Undervoltage Lockout
  • Available in a Thermally Enhanced 16-Lead TSSOP Package
Typical Application


Applications
  • Isolated Medium Power (10W to 60W) Supplies
  • Instrumentation Power Supplies
  • Isolated Medical Supplies
Packaging
Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LT3837EFE#PBFTSSOP-16E$4.43$3.10
LT3837EFE#TRPBFTSSOP-16E$3.16
LT3837IFE#PBFTSSOP-16I$4.69$3.28
LT3837IFE#TRPBFTSSOP-16I$3.34
Demo Boards
Part NumberDescriptionPrice
DC1038A-ALT3837EFE | 9V -36V input to 3.3V at 10A Sync. Flyback Converter$225.00
DC1038A-BLT3837EFE | 9V -36V input to 5V at 7A Sync. Flyback Converter$200.00
DC1038A-CLT3837EFE | 9V -36V input to 12V at 3A Sync. Flyback Converter$175.00
DC950A-BLT3837EFE Demo Board | 9V ≤ Vin ≤ 36V, Vout: 5V/2A, 3.3V/3A, 2.5V/3A$150.00
Datasheet
Design Note
Reliability Data
Press Release
Related Product
LT3837 - Isolated No-Opto Synchronous Flyback Controller
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R458 Reliability Data
Synchronous Isolated Flyback Controller for 9V-36V Inputs Needs No Optoisolator
LT3837 Footprints and Symbols