LT3439 - Slew Rate Controlled Ultralow Noise 1A Isolated DC/DC Transformer Driver


  • Reduced Conducted and Radiated EMI
  • Single Resistor Control of Output Switch Voltage and Current Slew Rates
  • Cross Conduction Prevention Circuitry
  • Two 1A Current Limited Power Switches
  • Low Minimum Supply Voltage: 2.8V
  • Low Shutdown Current: <20µA
  • 50% Duty Cycle
  • 20kHz to 250kHz Oscillator Frequency
  • Synchronizable to 300kHz
  • Overcurrent and Overtemperature Protected

Typical Application

LT3439 Typical Application
LT3439 Typical Application


The LT3439 is a push-pull DC/DC transformer driver that reduces conducted and radiated electromagnetic interference (EMI). Ultralow noise and EMI are achieved by controlling the output switch voltage and current slew rates. Slew rates are user adjustable to optimize output noise versus efficiency. The LT3439 can reduce high frequency harmonic content by as much as 40dB with only a minor decrease in efficiency.

The LT3439 includes two 1A current limited power switches to ensure start-up under heavy loads. It also includes an oscillator that can be synchronized to an external clock for more accurate placement of switcher harmonics. Protection features include current limiting, undervoltage lockout, thermal shutdown and cross conduction prevention circuitry.

The LT3439 is available in a thermally enhanced 16-pin TSSOP with an exposed backside.


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
LT3439EFE#PBF TSSOP-16 FE E 05-08-1663 (BA) Yes
LT3439EFE#TRPBF TSSOP-16 FE E 05-08-1663 (BA) Yes

LT3439 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
LT3439EFE#PBF TSSOP-16 E $5.00 $3.50 Yes
LT3439EFE#TRPBF TSSOP-16 E $3.62 Yes
Buy NowRequest Samples
* 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
DC511A LT3439EFE | Low Noise Isolated Power Supply, Vin = +5V +/-5%, +Vout = +12V@80mA, -Vout = -12V@80mA $125.00
Buy Now
Click here to view our complete list of demo boards


  • Low Noise Isolated Supplies
  • Radio and Telecom Supplies
  • Distributed Supplies
  • Medical Instruments
  • Precision Instruments
  • Low Noise Filament Supplies

Product Notifications

Please login to your MyLinear account for notifications of datasheet updates, new document releases and LTspice model announcements for your favorite products. If you do not have a MyLinear account you may Sign Up Now.

Forgot your password? Click here.
Need help? Email with questions and comments.

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.

Models for the following parts are available in LTspice:

Technical Support