Low-Noise Switching Regulators Power Mobile Devices

Groomed for portable electronics and based on a patent-pending architecture, the AAT2120 and AAT2158 synchronous step-down converters promise significantly lower spectral noise and output ripple than comparable switching regulators. At lower currents, the devices produce half the ringing amplitude and, at higher currents, produce approximately 25% less output ripple. Power efficiency for the AAT2120 and AAT2158 reach to 96% and 95% respectively. The AAT2120 supplies up to 500 mA of output current, while the AAT2158 delivers up to 1.5A. Both devices operate with an input range from 2.7V to 5.5 V and support output voltages as low as 0.6 V. For protection, both converters pack soft-start plus over-temperature and current limit protection. They also include 100 % duty cycle operation. With an operating temperature range from -40ºC to +85ºC, the AAT2120 is available in a lead-free, eight-pin, 2 mm x 2 mm STDFN package, and the AAT2158 comes in a lead-free, 16-pin, 3 mm x 3 mm QFN package. Prices are $0.85 and $1.55 each/1,000, respectively. ANALOGIC TECHNOLOGIES INC., Sunnyvale, CA. (408) 737-4600.