The NCP1526 product is a monolithic integrated circuit combining step-down PWM DC-DC converter dedicated to the portable applications powered from one cell Li-ion or three cell Alkaline/ NiCd/NiMH batteries and a low noise output voltage regulator dedicated to supply RF sensitive module in the portable applications. The DC-DC converter operates with a fixed output voltage of 1.2 V and delivers up to 400 mA. It uses synchronous rectification to increase efficiency and reduces external part count. The device also has a built -in 3.0 MHz (nominal) oscillator which reduces component size by allowing small inductor and capacitors. It includes an integrated soft-start, cycle-by-cycle current limiting, and thermal shutdown protection. The additional 2.80 V very low noise, low drop output regulator, is available with 150 mA current capability, current limitation and overtemperature protection.