Low Ripple And Fast Response Suit DC-DC Converters For Portable Devices

Supplying a clean output voltage with very low ripple and fast transient response, ON Semiconductor's NCP1523 and NCP1523B dc-dc converters are well-suited for power-sensitive applications such as micro hard-disk drives found in multimedia portable devices. The NCP1523 features automatic switching PWM/PFM modes, which improve system efficiency at a light load. The NCP1523B employs PWM-only mode, which provides an efficient load-transient solution and low output voltage ripple. The two converters also offer integrated soft-start, cycle-by-cycle current limiting, and thermal shutdown protection.

The use of a high switching frequency (3 MHz) allows the converters to employ a smaller inductor, as low as 1 µH. The converters implement synchronous rectification, which delivers up to 93% efficiency and extends battery life while reducing external parts count. Available in an adjustable output voltage from 0.9 V to 3.3 V, the NCP1523 and NCP1523B come packaged in a 2.1- by 1.1-mm, 8-pin Flip Chip. They cost $0.75 each in 1000-unit quantities. For more information, go to www.onsemi.com.