The NCP1522B step- down DC-DC converter is a monolithic integrated circuit optimized for portable applications powered from one cell Li- Ion or three cell Alkaline/NiCd/NiMH batteries. The part, available in adjustable output voltage versions ranging from 0.9 V to 3.3 V, is able to deliver up to 600 mA. It uses synchronous rectification to increase efficiency and reduce external part count. The device also has a built- in 3 MHz (nominal) oscillator which reduces component size by allowing smaller inductors and capacitors. Automatic switching PWM/PFM mode offers improved system efficiency. Additional features include integrated soft- start, cycle- by- cycle current limiting and thermal shutdown protection. The NCP1522B is available in a space saving, low profile TSOP5 and UDFN6 packages.