DC/DC Controller Makes Positive or Negative Regulated Voltages

May 18 2009 -MILPITAS, CA
  • Linear Technology Corporation announces the LT3757, a wide input range DC/DC controller for boost, flyback, SEPIC and inverting power supply applications, capable of generating either positive or negative regulated output voltages. The LT3757 has two voltage feedback error amplifiers and reference voltages. One set is for positive output voltages, with a 1.60V reference voltage, the other is for negative output voltages, with a –0.80V reference voltage, both off a single feedback pin, making the LT3757 a highly versatile DC/DC controller for many types of power supply designs.


    The LT3757 operates with an input voltage range from 2.9V to 40V, achieves efficiencies up to 96%, and is well suited for industrial, automotive, medical and telecom applications. With a programmable fixed or synchronizable operating frequency from 100kHz to 1MHz, designers can choose a wide range of inductors and capacitors to optimize size, performance and cost. The fixed frequency, current-mode control results in stable operation over a wide range of supply and output voltages, along with all ceramic capacitor designs, enabling a smaller solution size.


    The LT3757 drives an external N-channel MOSFET from an internally regulated 7.2V supply. Programmable soft-start allows for control of the output voltage turn-on time. In addition, the LT3757 features a programmable input undervoltage lockout with hysteresis, along with output overvoltage and overcurrent protection.


    The LT3757 is offered in thermally enhanced MSOP-10 and 3mm × 3mm DFN-10 packages, both with extended and industrial temperature ranges from –40°C to 125°C. The 1000-piece price starts at $2.06 each. For more information, visit www.linear.com.


    Summary of Features: LT3757


    • For Boost, Flyback, SEPIC & Inverting Applications
    • Wide Input Operating Voltage: 2.9V to 40V
    • Positive or Negative Output Voltage Setting with a Single Feedback Pin
    • Selectable Fixed 100kHz to 1MHz Operating Frequency
    • Synchronizable to an External Clock
    • Programmable Soft-Start
    • Integrated Low-Side Driver
    • True Current Mode Control
    • Internal 7.2V Low Dropout Voltage Regulator
    • Low Shutdown Current < 1uA
    • Output Overvoltage & Overcurrent Protection
    • Programmable Input Undervoltage Lockout with Hysteresis

    Boost, Flyback, SEPIC & Inverting Controller


    Download PDF version

  • Editor's Contact Information
Stay Informed