Buck Converter Efficiently Powers High Capacity SD Flash Memory Applications

Aug 25, 2010 1:22 PM

Fairchild Semiconductor developed the FAN5362, a 3MHz 500mA synchronous Buck regulator, using a proprietary architecture with synchronous rectification. The device is ideal for cell phone designers who need to support high capacity (e.g. 8, 16, 32GB, etc.) SD Flash Memory cards.

The nominal voltage level required for powering SD Flash Memory is 2.9V. With a VIN of 3.6V and a VOUT of 2.9V, the FAN5362 is capable of delivering a peak efficiency of 94 percent, while maintaining over 86 percent efficiency at light load (1mA).

Li-Ion batteries have an effective voltage range of 3.2 - 4.2V. It is the lower end of the battery voltage range which creates the low headroom application challenges. To prevent this, as the battery approaches the lower end of its range, the FAN5362 is able to transition seamlessly into and out of 100 percent duty cycle operation.

The FAN5362 works in conjunction with small input/output capacitors and 0805 multi-layer chip inductors. Compatibility with these passive components allows system designers to pick chip inductors and capacitors that consume less board space at a lower cost, resulting in smaller and more affordable end applications. This DC/DC converter is packaged in a 0.96 X 1.31mm WL-CSP package with a sleek, low profile of 0.6mm, conserving board space for these space-constrained applications.

While targeted towards 2.9V SD Flash Memory, the FAN5362 is also available in other fixed output voltage options ranging from 1.8 - 3.6V. This easy-to-design solution supports the quick design cycles found in the mobile device market, making it an ideal choice for cell phones, tablets, eBooks, PMPs, DSCs, GPS and lithium-ion portables.

Price: US$.49 in 1,000 piece quantities; samples available now; delivery 12 weeks ARO.

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