Features and Benefits

  • Pin Compatible with LTC3307(3A) and LTC3308(4A)
  • High Efficiency: 8mΩ NMOS, 31mΩ PMOS
  • Programmable Frequency 3MHz-10MHz
    • Tiny Inductor and Capacitors
  • Peak Current Mode Control
    • 22ns Minimum On-Time
    • Wide Bandwidth, Fast Transient Response
  • Silent Switcher Architecture
    • Ultralow EMI Emissions
  • Low Ripple Burst Mode® Operation with IQ of 40μA
  • Safely Tolerates Inductor Saturation in Overload
  • VIN Range: 2.25V to 5.5V
  • VOUT Range: 0.5V to VIN
  • VOUT Accuracy: ±1% Over Temperature Range
  • Precision 400mV Enable Threshold, 1μA in Shutdown
  • Power Good, Internal Compensation and Soft Start
  • Thermally Enhanced 2mm × 2mm LQFN Package
  • AEC-Q100 Qualified for Automotive Applications
  • Product Details

    The LTC3309B is a very small, high efficiency, low noise, monolithic synchronous 6A step-down DC/DC converter operating from a 2.25V to 5.5V input supply. Using constant frequency, peak current mode control at switching frequencies 3MHz-10MHz and minimum on-time as low as 22ns, this regulator achieves fast transient response with small external components. Silent Switcher architecture minimizes EMI emissions.

    The LTC3309B operates in forced continuous or pulse skip mode for low noise, or the low-ripple Burst Mode operation for high efficiency at light loads, ideal for battery-powered systems. The IC regulates output voltages as low as 500mV. Other features include output over-voltage protection, short-circuit protection, thermal shut-down, clock synchronization, and up to 100% duty cycle operation for low dropout. The device is available in a low profile 12-lead 2mm × 2mm × 0.74mm LQFN package with exposed pad for low thermal resistance.


    • Optical Networking, Servers, Telecom
    • Automotive, Industrial, Communications
    • Distributed DC Power Systems (POL)
    • FPGA, ASIC, µP Core Supplies

    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.


    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:


    Design Resources

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    Evaluation Boards

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    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.