LT3750 - Capacitor Charger Controller


  • Charges Any Size Capacitor
  • Easily Adjustable Output Voltage
  • Drives High Current NMOS FETs
  • Primary-Side Sense—No Output Voltage Divider Necessary
  • Wide Input Range: 3V to 24V
  • Drives Gate to VCC – 2V
  • Available in 10-Lead MS Package

Typical Application

LT3750 Typical Application
LT3750 Typical Application


The LT3750 is a flyback converter designed to rapidly charge large capacitors to a user-adjustable target voltage. A patented boundary mode control scheme* minimizes transition losses and reduces transformer size. The transformer turns ratio and two external resistors easily adjust the output voltage. A low 78mV current sense accurately limits peak switch current and also helps to maximize efficiency. With a wide input voltage range, the LT3750 can operate from a variety of power sources. A typical application can charge a 100μF capacitor to 300V in less than 300ms.

The CHARGE pin gives full control of the LT3750 to the user. The DONE pin indicates when the capacitor has reached its programmed value and the part has stopped charging.


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
LT3750EMS#PBF MS-10 MS E 05-08-1661 Yes
LT3750EMS#TRPBF MS-10 MS E 05-08-1661 Yes

LT3750 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
LT3750EMS#PBF MS-10 E $5.00 $3.50 Yes
LT3750EMS#TRPBF MS-10 E $3.56 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
DC891A LT3750EMS Demo Board | Capacitor Charger, 6V to 20VIN, 300VOUT, 2.2A Charging Current $125.00
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Click here to view our complete list of demo boards


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Design Tools


LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

To launch a ready to run LTspice demonstration circuit for this part:

  • Step 1: If you have not installed LTspice on this computer, download and install LTspice
  • Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
  • Step 3: If LTspice does not automatically open after clicking the link above, you can instead run the simulation by right clicking on the link and selecting "Save Target As." After saving the file to your computer, start LTspice and open the demonstration circuit by selecting 'Open' from the 'File' menu

To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.

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