LT3752/LT3752-1 - Active Clamp Synchronous Forward Controllers with Internal Housekeeping Controller


  • Input Voltage Range: LT3752: 6.5V to 100V, LT3752-1:Limited Only by External Components
  • Internal Housekeeping DC/DC Controller
  • Programmable Volt-Second Clamp
  • High Efficiency Control: Active Clamp, Synchronous Rectification, Programmable Delays
  • Short-Circuit (Hiccup Mode) Overcurrent Protection
  • Programmable Soft-Start/Stop
  • Programmable OVLO and UVLO with Hysteresis
  • Programmable Frequency (100kHz to 500kHz)
  • Synchronizable to an External Clock

Typical Application

LT3752 Typical Application


The LT®3752/LT3752-1 are current mode PWM controllers optimized for an active clamp forward converter topology. A DC/DC housekeeping controller is included for improved efficiency and performance. The LT3752 allows operation up to 100V input and the LT3752-1 is optimized for applications with input voltages greater than 100V.

A programmable volt-second clamp allows primary switch duty cycles above 50% for high switch, transformer and rectifier utilization. Active clamp control reduces switch voltage stress and increases efficiency. A synchronous output is available for controlling secondary side synchronous rectification.

The LT3752/LT3752-1 are available in a 38-lead plastic TSSOP package with missing pins for high voltage spacings.


CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

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

Part Number Package Code Temp Package
LT3752EFE-1#PBF TSSOP-38 FE E 05-08-1865 Yes
LT3752EFE-1#TRPBF TSSOP-38 FE E 05-08-1865 Yes
LT3752EFE#PBF TSSOP-38 FE E 05-08-1865 Yes
LT3752EFE#TRPBF TSSOP-38 FE E 05-08-1865 Yes
LT3752HFE-1#PBF TSSOP-38 FE H 05-08-1865 Yes
LT3752HFE-1#TRPBF TSSOP-38 FE H 05-08-1865 Yes
LT3752HFE#PBF TSSOP-38 FE H 05-08-1865 Yes
LT3752HFE#TRPBF TSSOP-38 FE H 05-08-1865 Yes
LT3752IFE-1#PBF TSSOP-38 FE I 05-08-1865 Yes
LT3752IFE-1#TRPBF TSSOP-38 FE I 05-08-1865 Yes
LT3752IFE#PBF TSSOP-38 FE I 05-08-1865 Yes
LT3752IFE#TRPBF TSSOP-38 FE I 05-08-1865 Yes
LT3752MPFE-1#PBF TSSOP-38 FE MP 05-08-1865 Yes
LT3752MPFE-1#TRPBF TSSOP-38 FE MP 05-08-1865 Yes
LT3752MPFE#PBF TSSOP-38 FE MP 05-08-1865 Yes
LT3752MPFE#TRPBF TSSOP-38 FE MP 05-08-1865 Yes

LT3752 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
LT3752EFE-1#PBF TSSOP-38 E $4.84 $3.39 Yes
LT3752EFE-1#TRPBF TSSOP-38 E $3.45 Yes
LT3752EFE#PBF TSSOP-38 E $4.84 $3.39 Yes
LT3752EFE#TRPBF TSSOP-38 E $3.45 Yes
LT3752HFE-1#PBF TSSOP-38 H $5.71 $4.00 Yes
LT3752HFE-1#TRPBF TSSOP-38 H $4.06 Yes
LT3752HFE#PBF TSSOP-38 H $5.71 $4.00 Yes
LT3752HFE#TRPBF TSSOP-38 H $4.06 Yes
LT3752IFE-1#PBF TSSOP-38 I $5.30 $3.71 Yes
LT3752IFE-1#TRPBF TSSOP-38 I $3.77 Yes
LT3752IFE#PBF TSSOP-38 I $5.30 $3.71 Yes
LT3752IFE#TRPBF TSSOP-38 I $3.77 Yes
LT3752MPFE-1#PBF TSSOP-38 MP $14.29 $10.00 Yes
LT3752MPFE-1#TRPBF TSSOP-38 MP $10.06 Yes
LT3752MPFE#PBF TSSOP-38 MP $14.29 $10.00 Yes
LT3752MPFE#TRPBF TSSOP-38 MP $10.06 Yes
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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
DC1929A LT3752EFE-1/ LT8311EFE Demo Board | 150V ≤ VIN ≤ 400V, VOUT = 12V @ 16.7A $300.00
DC1994A LT3752EFE/LT8311EFE Isolated Demo Board | 18V ≤ VIN ≤ 72V; VOUT: 12V @ 12A $300.00
DC2175A LT3752IFE/LT8311IFE Demo Board | Forward Converter with Sync Rectification, 9V ≤ VIN ≤ 36V; Vout = 12V @ 13A $300.00
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Click here to view our complete list of demo boards


  • Offline and HV Car Battery Isolated Power Supplies
  • 48V Telecommunication Isolated Power Supplies
  • Industrial, Automotive and Military Systems

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