Breakthrough 20V Nanopower Switching Regulator Provides 50mA Output with Only 720nA of Quiescent Current

Aug 19 2010 - MILPITAS, CA
  • Linear Technology announces the LTC3388, an ultralow quiescent current synchronous buck converter that can deliver up to 50mA of continuous output current from a 2.7V to 20V input supply. The LTC3388's no-load operating current of only 720nA makes it ideal for a wide range of battery-powered and low quiescent power applications including "keep-alive," energy harvesting and industrial control power. The LTC3388 utilizes hysteretic synchronous rectification to optimize efficiency over a wide range of load currents. It can offer over 90% efficiency for loads ranging from 15uA to 50mA and only requires 720nA of no load quiescent current in regulation, thereby extending battery life. The combination of a 3mm × 3mm DFN package (or MSOP-10) and only five external components offers a very simple and compact solution footprint for a wide array of low power applications.

    The LTC3388 incorporates an accurate under voltage lock-out feature to disable the converter when the input voltage drops below 2.3V, reducing quiescent current to only 400nA. Once in regulation (at no load), the LTC3388 enters a sleep mode to minimize quiescent current to only 720nA. The buck converter then turns on and off as needed to maintain output regulation. An additional standby mode disables buck switching while the output is in regulation for short duration loads, such as wireless modems, which require low ripple.  This high efficiency, low quiescent current design is ideal for applications such as remote monitors, which require long standby times accompanied by short burst loads for powering sensors and wireless transceivers. The LTC3388 is offered in two different versions, each with different pin-selectable output voltages. The LTC3388-1 offers 1.2V, 1.5V, 1.8V or 2.5V outputs whereas the LTC3388-3 offers 2.8V, 3.0V, 3.3V or 5V outputs.

    Pricing for the LTC3388EDD-1, LTC3388EDD-3, LTC3388EMSE-1 and the LTC3388EMSE-3 starts at $2.95, each, for 1,000-piece quantities. Industrial grade versions, namely the LTC3388IDD-1, LTC3388IDD-3, LTC3388IMSE-1 and LTC3388IMSE-3 are tested and guaranteed to operate from a –40°C to 125°C operating junction temperature. They are priced at $3.39 each, respectively in 1,000-piece quantities. All versions are available from stock. For more information, visit

    Summary of Features: LTC3388

    • 720nA Input IQ in Regulation (No Load), VIN = 4V
    • 820nA Input IQ in Regulation (No Load), VIN = 20V
    • 400nA Input IQ in UVLO
    • 2.7V to 20V Input Operating Range
    • Up to 50mA of Output Current
    • Pin Selectable Output Voltages:
    • 1.2V, 1.5V, 1.8V, 2.5V (LTC3388-1)
    • 2.8V, 3.0V, 3.3V, 5.0V (LTC3388-3)
    • Open Drain Power Good Output
    • High Efficiency Hysteretic Synchronous DC/DC Conversion
    • Standby Mode Disables Buck Switching
    • Available in 10-Lead MSOP-E and 3mm × 3mm DFN Packages

    20V High Efficiency, Low Quiescent Current Synchronous Step-Down DC/DC Converter


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