Multiphase Step-Up DC/DC Controller Delivers High Power

Jun 25 2008 -MILPITAS, CA
  • Linear Technology Corporation introduces the LTC3862, a 2-phase step-up (boost) DC/DC controller that delivers high output power in a compact footprint. Up to 12 power stages can be paralleled and clocked out-of-phase to minimize input and output filtering requirements. The 4V to 36V input voltage range and a wide output voltage range that is dependent on the choice of external components covers a broad range of high power boost applications. The LTC3862 can regulate a 48V at 5A output with up to 97% efficiency from an input source ranging from 12V to 36V using only two-phases. Applications include high power audio amplifiers, automotive fuel injection systems, networking and industrial power supplies.

    Multiphase operation is enabled using the SYNC input, CLOCK output and PHASEMODE control pin, allowing 2, 3, 4, 6 or 12-phase operation. The LTC3862 utilizes peak current mode architecture for easy loop compensation and multi-phase operation with excellent phase-to-phase current matching. The fixed operating frequency can be set with a single resistor over a 75kHz to 500kHz range or can be synchronized to an external clock using the internal phased-lock-loop over a 50kHz to 600kHz frequency range. A current sense resistor is used in each phase to provide a precise cycle-by-cycle current limit. The powerful on-board CMOS gate drivers minimize switching losses and allow the use of multiple MOSFETs in parallel for even higher current applications. Other features include an on-board 5V LDO that eliminates the need for a bias voltage to power the IC, undervoltage lockout protection, a precise RUN pin threshold with programmable hysteresis, adjustable soft-start, programmable maximum duty cycle and user-adjustable leading edge blanking.

    The LTC3862 is offered in narrow SSOP-24 and 5mm × 5mm QFN-24 package. Three temperature grades are available with commercial grade operation from 40 to 85°C, an industrial range from 40°C to 125°C, and a high temp automotive range of 40°C to 150°C. The 1,000-piece price starts at $3.29 each.

    Summary of Features: LTC3862

    • Multiphase Operation – Up to 12 Phases
    • High Output Power
    • Wide Input Voltage Range from 4V to 36V
    • Minimum External Components
    • Fixed Programmable Operating Frequency from 75kHz to 500kHz
    • Synchronizable with Phase-Lock-Loop (PLL) from 50kHz to 650kHz
    • Peak Current Mode Control
    • Programmable Maximum Duty Cycle
    • Adjustable Soft-Start
    • High Operating Temperature up to 150°C

    Multiphase Step-Up DC/DC Controller

    LTC3862 PR Image

    Download PDF version

  • Editor's Contact Information
Stay Informed