Features and Benefits

  • Wide VIN Range: 2.7V to 17V
  • Wide VOUT Range: 0.6V to VIN
  • 95% Max Efficiency
  • Low IQ < 3.5μA, Zero-Current Shutdown
  • Constant Frequency (1MHz/2.25MHz)
  • Full Dropout Operation with Low IQ
  • 1A Rated Output Current
  • ±1% Output Voltage Accuracy
  • Current Mode Operation for Excellent Line and Load Transient Response
  • Synchronizable to External Clock
  • Pulse-Skipping, Forced Continuous, Burst Mode® Operation
  • Internal Compensation and Soft-Start
  • Overtemperature Protection
  • Compact 6-Lead DFN (2mm × 3mm) Package or Thermally-Enhanced MS8E Package with Power Good Output and Independent SGND Pin
  • AEC-Q100 Qualified for Automotive Applications

Product Details

The LTC3621/LTC3621-2 is a high efficiency 17V, 1A synchronous monolithic step-down regulator. The switching frequency is fixed to 1MHz or 2.25MHz with a ±40% synchronizing range. The regulator features ultralow quiescent current and high efficiencies over a wide VOUT range.

The step-down regulator operates from an input voltage range of 2.7V to 17V and provides an adjustable output range from 0.6V to VIN while delivering up to 1A of output current. A user-selectable mode input is provided to allow the user to trade off ripple noise for light load efficiency; Burst Mode operation provides the highest efficiency at light loads, while pulse-skipping mode provides the lowest voltage ripple. The MODE pin can also be used to allow the user to sync the switching frequency to an external clock.

LTC3621 Options
Part Name Frequency VOUT
LTC3621 1.00MHz Adjustable
LTC3621-3.3 1.00MHz 3.3V
LTC3621-5 1.00MHz 5V
LTC3621-2 2.25MHz Adjustable
LTC3621-23.3 2.25MHz 3.3
LTC3621-25 2.25MHz 5V


  • Portable-Handheld Scanners
  • Industrial and Embedded Computing
  • Automotive Applications
  • Emergency Radio

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 (3)

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.

To open the project file for this circuit:

Step 1: Download and install LTpowerCAD on your computer.

Step 2: Click on the link(s) in the section below to download part-specific project files.

Step 3: If the project file doesn't run, right-click the link and select "Save Target As." Then start the LTpowerCAD tool and open the project file by selecing "Open Project" from the "File" menu.


Design tools for the following parts are available in LTpowerCAD:


Reference Designs (1)

Product Recommendations

LTC3621 Companion Parts

Recommended Related Parts

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.

PCN-PDN Information

Sample & Buy

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Price Table Help


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.