96% efficient 1A buck converter extends battery life

ams has announced a 1A synchronous buck converter with the wide input voltage range, high efficiency and low stand-by current required in designs powered by a single-cell lithium-ion battery. The AS1382 step-down converter operates from an input range of 2.7-5.5V and provides an output down to as little as 0.6V.

Offering efficiency as high as 96% and no-load current of just 95µA, the converter helps designers of li-ion battery powered devices to reduce losses in the power circuit and to extend their product’s run-time between charges. In shut-down mode, the device draws just 0.04µA.

Housed in a miniature 1.22x0.85mm six-lead chip-scale package (WL-CSP6) with a 0.4mm pitch, the AS1382 operates at an internally fixed frequency of 2, 3 or 4MHz, enabling the use of a small inductor. This means that a circuit based on the AS1382 DC/DC converter is small enough to be accommodated in densely populated board designs, such as those found in mobile phones, portable media players and wearable devices.

The AS1382 is provided in variants offering a fixed output of 1.0, 1.2, 1.5 or 1.8V and in a version with an output adjustable over the range 0.61-3.35V. All support a continuous load current of 1A and require an output capacitor of just 10µF.

The step-down converter may be operated in one of two modes: its low-ripple/low-noise mode produces very low levels of ripple and noise. In high-efficiency mode, the device has lower power losses when supplying light loads, increasing stand-by time in always-on battery operated solutions. The device includes an internal synchronous switch, which eliminates the need for an external Schottky diode.

Bernd Krafthoefer, Product Marketing Manager, ams, comments: "The synchronous converters used in portable and battery-powered products continue to yield opportunities for reducing power losses. Designers who can make use of the AS1382’s 96% peak efficiency and extremely low stand-by current will find they can gain worthwhile extra run-time out of their product’s li-ion battery system."

The AS1382 DC/DC step-down converter is available now in production volumes, priced at $0.21 each in 1,000 unit quantities.

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