Features and Benefits

  • 4-Switch Single Inductor Architecture Allows VIN Above, Below or Equal to VOUT
  • Proprietary Peak-Buck Peak-Boost Current Mode
  • 3V to 36V Input Voltage Range
  • 0V to 36V Output Voltage Range
  • ±1.5% Output Voltage Regulation
  • ±3% LED Current Regulation
  • 5000:1 External and 128:1 Internal PWM Dimming
  • Rail-to-Rail LED Current Sense and Monitor Output
  • Open and Short LED Protection with Fault Reporting
  • 300kHz to 2MHz Fixed Switching Frequency with External Frequency Synchronization
  • Flicker-Free Spread Spectrum for Low EMI
  • Available in 28-Lead QFN (4mm × 5mm)

Product Details

The LT3942 is a monolithic 4-switch synchronous buck-boost LED driver. The driver can regulate the LED string current up to 34V with input voltages above, below, or equal to the output voltage. The proprietary peak-buck peak-boost current mode control scheme allows adjustable and synchronizable 300kHz to 2MHz fixed frequency operation, or internal 25% triangle spread spectrum operation for low EMI. With 3V to 36V input, 0V to 36V output and seamless low-noise transitions between operation regions, the LT3942 is ideal for LED driver applications in automotive, industrial and battery-powered systems. 

The LT3942 provides LED current regulation with up to 128:1 internal and 5000:1 external PWM dimming using an optional high-side PMOS switch. The CTRL pin provides flexible 20:1 analog dimming with ±2.5% LED current regulation at 100mV full scale. Robust fault protection detects an open or short LED condition, during which the LT3942 retries, latches off, or keeps running.


  • General Purpose LED Driver
  • Automotive and Industrial Lighting
  • Voltage Regulator with Accurate Current Limit

Product Lifecycle icon-recommended Recommended for New Designs

This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.

Evaluation Kits (1)

Tools & Simulations


LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.

To launch ready-to-run LTspice demonstration circuits for this part:

Step 1: Download and install LTspice on your computer.

Step 2: Click on the link in the section below to download a demonstration circuit.

Step 3: If LTspice does not automatically open after clicking the link below, 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.


Models for the following parts are available in LTspice:



LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.


Design tools for the following parts are available in LTpowerCAD:


Design Resources

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.

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Evaluation Boards Pricing displayed is based on 1-piece.
Up to two boards can be purchased through Analog.com. To order more than two, please purchase through one of our listed distributors.
Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.