LTC3765 - Active Clamp Forward Controller and Gate Driver


  • 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

Typical Application

LTC3765 Typical Application


The LTC®3765 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.


For complete and up to date package information and drawings, please refer to our packaging page


LTC3765 Package Drawing

Order Info

Package Variations and Pricing

Part Number Package Pins Temp Price (1-99) Price (1k)* RoHS Data
LTC3765EMSE#PBF MSOP 16 E $3.66 $2.56 View
LTC3765EMSE#TRPBF MSOP 16 E $2.62 View
LTC3765HMSE#PBF MSOP 16 H $4.50 $3.15 View
LTC3765HMSE#TRPBF MSOP 16 H $3.21 View
LTC3765IMSE#PBF MSOP 16 I $4.04 $2.83 View
LTC3765IMSE#TRPBF MSOP 16 I $2.89 View
LTC3765MPMSE#PBF MSOP 16 MP $11.03 $7.72 View
LTC3765MPMSE#TRPBF MSOP 16 MP $7.78 View
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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 Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Part Number Description Price Documentation
DC1739A-B LTC3765EMSE/LTC3766EGN Demo Board | 18V ≤ VIN ≤ 72V; VOUT = 12V @ 12.5A $300.00
DC1739B-C LTC3765EMSE/LTC3766EGN Demo Board | 9V ≤ VIN ≤ 36V; VOUT = 12V @ 10A Contact Factory
DC2199A-A LTC3765EMSE/LTC3766EGN Isolated Demo Board | 36V ≤ VIN ≤ 60V; VOUT = 12V @ 30A Contact Factory
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Click here to view our complete list of demo boards


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

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