LTC3766 - High Efficiency, Secondary-Side Synchronous Forward Controller


  • Direct Flux Limit™ Guarantees No Saturation
  • Fast and Accurate Average Current Limit
  • Clean Start-Up Into Pre-Biased Output
  • Secondary-Side Control for Fast Transient Response
  • Simple, Self-Starting Architecture
  • Synchronous MOSFET Reverse Current Limit
  • PolyPhase® Operation Eases High-Power Design
  • True Remote Sense Differential Amplifier
  • Remote Sense Reverse Protection
  • High Voltage Linear Regulator Controller
  • Internal LDO Powers Gate Drive from VOUT
  • Overtemperature/Overvoltage Protection
  • Low Profile 4mm × 5mm QFN and Narrow 28-Lead SSOP Packages

Typical Application

LTC3766 Typical Application


The LTC®3766 is a PolyPhase-capable secondary-side controller for synchronous forward converters. When used in conjunction with the LTC3765 active-clamp forward controller and gate driver, the part creates a complete isolated power supply that combines the power of multiphase operation with the speed of secondary-side control.

The LTC3766 has been designed to simplify the design of active clamp forward converters. Working in concert with the LTC3765, the LTC3766 forms a robust, self-starting converter that eliminates the need for the separate bias regulator that is commonly used in secondary-side control applications. A precision current-limit coupled with clean start-up into a pre-biased load make the LTC3766 an excellent choice for high-power battery charger applications.

The LTC3766 provides extensive remote sensing and output protection features, while Direct Flux Limit guarantees no transformer saturation without compromising transient response. A linear regulator controller and internal bypass LDO are also provided to simplify the generation of the secondary-side bias voltage.


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

4x5 QFN-28, SSOP-28

LTC3766 Package Drawing
LTC3766 Package Drawing

Order Info

Package Variations and Pricing

Part Number Package Pins Temp Price (1-99) Price (1k)* RoHS Data
LTC3766EGN#PBF SSOP 28 E $5.54 $3.88 View
LTC3766EGN#TRPBF SSOP 28 E $3.94 View
LTC3766EUFD#PBF QFN 28 E $5.54 $3.88 View
LTC3766EUFD#TRPBF QFN 28 E $3.94 View
LTC3766HGN#PBF SSOP 28 H $6.54 $4.58 View
LTC3766HGN#TRPBF SSOP 28 H $4.64 View
LTC3766HUFD#PBF QFN 28 H $6.54 $4.58 View
LTC3766HUFD#TRPBF QFN 28 H $4.64 View
LTC3766IGN#PBF SSOP 28 I $6.11 $4.28 View
LTC3766IGN#TRPBF SSOP 28 I $4.34 View
LTC3766IUFD#PBF QFN 28 I $6.11 $4.28 View
LTC3766IUFD#TRPBF QFN 28 I $4.34 View
LTC3766MPGN#PBF SSOP 28 MP $16.51 $11.56 View
LTC3766MPGN#TRPBF SSOP 28 MP $11.62 View
LTC3766MPUFD#PBF QFN 28 MP $16.51 $11.56 View
LTC3766MPUFD#TRPBF QFN 28 MP $11.62 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 48V Telecommunication Systems
  • Isolated Battery Chargers
  • Automotive and Military Systems
  • Industrial, Avionics and Heavy Equipment

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