MAX1921

Low-Voltage, 400mA Step-Down DC-DC Converters in SOT23


Please check latest availability status for a specific part variant.

Description

The MAX1920/MAX1921 step-down converters deliver over 400mA to outputs as low as 1.25V. These converters use a unique proprietary current-limited control scheme that achieves over 90% efficiency. These devices maintain extremely low quiescent supply current (50µA), and their high 1.2MHz (max) operating frequency permits small, low-cost external components. This combination makes the MAX1920/MAX1921 excellent high-efficiency alternatives to linear regulators in space-constrained applications.

Internal synchronous rectification greatly improves efficiency and eliminates the external Schottky diode required in conventional step-down converters. Both devices also include internal digital soft-start to limit input current upon startup and reduce input capacitor requirements.

The MAX1920 provides an adjustable output voltage (1.25V to 4V). The MAX1921 provides factory-preset output voltages (see the Selector Guide). Both are available in space-saving 6-pin SOT23 packages. The MAX1920 is also available in a 6-pin TDFN package.
MAX1920, MAX1921: Typical Operating Circuit MAX1920, MAX1921: Typical Operating Circuit Enlarge+

Key Features

  • 400mA Guaranteed Output Current
  • Internal Synchronous Rectifier for >90% Efficiency
  • Tiny 6-Pin SOT23 Package
  • Available in 6-Pin TDFN Package (MAX1920)
  • Up to 1.2MHz Switching Frequency for Small External Components
  • 50µA Quiescent Supply Current
  • 0.1µA Logic-Controlled Shutdown
  • 2V to 5.5V Input Range
  • Fixed 1.5V, 1.8V, 2.5V, 3V, and 3.3V Output Voltages (MAX1921)
  • Adjustable Output Voltage (MAX1920)
  • ±1.5% Initial Accuracy
  • Soft-Start Limits Startup Current
  • Applications/Uses

    • Battery-Powered Applications
    • CDMA Power Amplifier Supply
    • Next-Generation Wireless handsets
    • PDAs, Palmtops, and Handy Terminals
    Part NumberVIN
    (V)
    VIN
    (V)
    VOUT1
    (V)
    VOUT1
    (V)
    Preset VOUT
    (V)
    Output Adjust. MethodIOUT1
    (A)
    Switch TypeSynchronous SwitchingDC-DC OutputsOper. Freq.
    (kHz)
    Package/PinsBudgetary
    Price
    minmaxminmaxSee Notes
    MAX1920 25.51.254-Resistor0.4InternalYes11200
    SOT23/6
    TDFN/6
    $1.35 @1k
    MAX1921 1.53.3
    1.5
    1.8
    2.5
    3
    3.3
    Preset
    Resistor
    SOT23/6
    See All Step-Down Switching Regulators (367)
    Pricing Notes:
    This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.


    MAX1921EVKIT: Evaluation Kit for the MAX1920, MAX1921

    Technical Documents

    App Note 3741 Analog ICs for Low Voltage Systems

    Quality and Environmental Data

    Product Reliability Reports: MAX1921.pdf 
    Lead-Free Package Tin (Sn) Whisker Reports

    Additional Resources

    Topmark Coding MAX1921

    CAD Symbols and Footprints

  • MAX1921EUT15+
  • MAX1921EUT15+T
  • MAX1921EUT15-T
  • MAX1921EUT18+
  • MAX1921EUT18+T
  • MAX1921EUT18-T
  • MAX1921EUT25+
  • MAX1921EUT25+T
  • MAX1921EUT25-T
  • MAX1921EUT30
  • MAX1921EUT30+
  • MAX1921EUT30+T
  • MAX1921EUT30-T
  • MAX1921EUT33+
  • MAX1921EUT33+T
  • MAX1921EUT33-T
  • Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

    Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

    Quality Management System >
    Environmental Management System >

     
    Status:
    Package:
    Temperature:

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    Type ID PDF Title
    App Note 3741 Analog ICs for Low Voltage Systems