The RT9901 is a complete power-supply solution for digital still cameras and other hand-held devices. It integrates a high-efficiency main step-up DC-DC converter, two highefficiency step-down converters, a charge pump, and voltage detector. The RT9901 is targeted for applications that use either two or three AA cells or a single lithiumion battery. The main step-up DC-DC converter accepts inputs from 1.5V to 5.5V and build in 2.6A Internal switch. The two step-down DC-DC converters (CH2, CH3) accept inputs from 1.5V to 5.5V and regulate a resistor-adjustable output from 0.8V to 5.5V. Each DC-DC converters have independent shutdown inputs. The feature of the charge pump is to deliver few current to micro-controller when the system operates in the standby mode. RT9901 include a low battery detector with 0.8V detection voltage. An adjustable operating frequency (up to 1.4MHZ) is utilized to get optimum size, cost, and efficiency. RT9901 is available in VQFN-32L 5x5 package.