The NCP1529 step-down DC-DC converter is a monolithic integrated circuit for portable applications powered from one cell Li-ion or three cell Alkaline/NiCd/NiMH batteries. The device is able to deliver up to 1.0 A on an output range externally adjustable from 0.9 V to 3.9 V or fixed at 1.2 V or 1.35 V.It uses synchronous rectification to increase efficiency and reduce external part count. The device also has a built-in 1.7 MHz (nominal) oscillator which reduces component size by allowing a small inductor 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 NCP1529 is available in a space saving, low profile 2x2x0.5 mm UDFN6 package and TSOP-5 package.