High-switching frequency capability enables integrated device to use thinner inductors

March 20, 2012 // By Paul Buckley
Fairchild Semiconductor's, FDMF6708N Generation II XS DrMOS family is a fully optimized, compact, integrated MOSFET plus driver power stage solution for high-current, high-frequency, synchronous buck DC-DC applications. The device is ideal for designers facing the challenge of reducing inductor height in power supply designs in order to meet the low-profile, thinner end-system demands of applications such as Ultrabook devices and notebooks.

The FDMF6708N integrates a driver IC, two power MOSFETs, and a bootstrap Schottky diode into a thermally enhanced, 6x6 mm 2 PQFN Intel DrMOS v4.0 standard package.

The FDMF6708N provides designers a 50 percent smaller footprint while delivering high-switching frequency and high power density. The device's Zero Cross Detect (ZCD) feature improves light load efficiency for extended battery life. Unlike the traditional discrete solution, this device also provides high efficiency at full load using the latest control FET and SyncFET technology as well as clip-bond packaging with lower source inductance. Traditional discrete solutions require larger PCB space, longer layout traces, higher inductances, and more components resulting in poor thermal performance at the higher frequencies required to enable lower profile magnetics.

Available in a PQFN 6x6 mm 2 package, the FDMF6708N device offers 2.5 percent better efficiency at peak load (15 A) and six percent better efficiency at full load (30 A) than the nearest competitor. The device is suitable for use in applications requiring 600 KHz – 1.0 MHz switching frequency, even with a 20 V input voltage. This enables designers to use smaller and thinner inductors and capacitors for reduced solution size, while meeting thermal requirements. The FDMF6708N device helps resolve the challenges of designing an Ultrabook that is cooler, thinner, and more energy efficient.

The FDMF6708N features more than a 1.0MHz switching frequency capability which reduces overall solution size, saving up to 50 percent of board space, and resulting in thinner systems by reducing inductor height.  The device includes Zero Cross Detect (ZCD) circuitry for improved light load performance.  The device’s PQFN 6x6 mm 2 Intel DrMOS v4.0 standard footprint, multi source solution  Multi Chip Module (MCM) offers 2.5 percent better efficiency at peak load (15 A) and six percent better efficiency at 30 A full load, (19 Vin, 1 Vout, 800 KHz) when compared to the nearest competitor resulting in longer battery life.

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