2.5µA Quiescent Current, 62V, 350mA (IOUT), 2.2MHz Step-Down DC/DC Converter

Dec 8 2009 - MILPITAS, CA
  • Linear Technology Corporation announces the LT3990, a 350mA, 60V ultralow quiescent current step-down switching regulator. Its Burst Mode® operation keeps quiescent current under 2.5µA in no load condition. The LT3990's 4.3V to 60V input voltage range makes it ideal for automotive and industrial applications that need continuous output with ultralow power drain. Its internal 550mA switch can deliver up to 350mA of continuous output current at voltages as low as 1.21V. The LT3990's Burst Mode operation provides ultralow quiescent current, well suited for automotive or industrial systems, which demand always-on operation and optimum battery life. Switching frequency is user programmable from 200kHz to 2.2MHz, enabling the designer to optimize efficiency while avoiding critical noise-sensitive frequency bands. The combination of its 10-lead 3mm × 2mm DFN-10 (or MSOP) package and high switching frequency keeps external inductors and capacitors small, providing a very compact, thermally efficient footprint.

    The LT3990 utilizes a high efficiency 550mA, 300mV switch, with the necessary boost and catch Schottky diodes, oscillator, control and logic circuitry integrated into a single die. Low ripple Burst Mode operation ensures high efficiency at low output currents while keeping output ripple below 5mVPK-PK. Special design techniques and a new high voltage process enable high efficiency over a wide input voltage range, and the LT3990's current mode topology enables fast transient response and excellent loop stability. Other features include a power good flag soft-start capability and output short protection.

    The LT3990EDDB is packaged in a 3mm × 2mm DFN-10, and the LT3990EMS is packaged in a MSOP-10, priced starting at $2.55 and $2.60 each, respectively for 1,000 piece quantities. The LT3990IDDB and LT3990IMS are tested and guaranteed to operate from a –40ºC to 125ºC operating junction temperature and are priced at $2.83 and $2.89 each, respectively in 1,000 piece quantities. All versions are available from stock. For more information, visit www.linear.com.

    Summary of Features: LT3990

    • Low Ripple Burst Mode® Operation
    • 2.5µA IQ at 12VIN to 3.3VOUT
    • Output Ripple < 5mVP-P
    • Wide Input Voltage Range: 4.3V to 60V Operating
    • Adjustable Switching Frequency: 200kHz to 2.2MHz
    • Integrated Boost & Catch Diodes
    • 350mA Output Current
    • Accurate 1V Enable Pin Threshold
    • Low Shutdown Current: IQ = 0.7µA
    • Internal Sense Limits Catch Diode Current
    • Power Good Flag
    • Output Voltage: 1.21V to 25V
    • Internal Compensation
    • Small 10-Pin MSOP & (3mm × 2mm) DFN Packages

    60V 350mA (IOUT), 2.2MHz Step-Down Switching Regulator in 3mm × 2mm DFN


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