RT9903B

Preliminary RT9903B 4 Channel DC/DC Converters IC with High-Efficiency Step-Up General Description The RT9903B is a complete power-supply solution for digital still cameras and other hand-held devices. It integrates a high-efficiency fours step-up DC-DC converters and a charge pump. www.DataSheet4U.com Features z Two step-up DC-DC Converters (CH1, CH2) `HV Internal Switches `50mA Load Current One Step-up DC-DC Converter (CH3) `0.2V Reference Voltage `HV Internal Switches `LED Brightness Dimming Control `Over Voltage Protection One Step-up DC-DC Converter (CH4) `External Switches `External Current Limit Setting Up to 1.4MHz Switching Frequency 1μA Supply Current in Shutdown Mode External Compensation Network for All Converters Programmable Soft Start Function (CH1, CH2, CH3, CH4) Independent Enable Pin to Shutdown Each Channel 24-Lead VQFN Package RoHS Compliant and 100% Lead (Pb)-Free z The two Step-up DC-DC converters (CH1,CH2) accept inputs from 1.5V to 5.5V and regulate a resistoradjustable output up to 17V. One Step-up DC-DC converter (CH3) can be regarded as white LED Driver, which reference voltage is 0.2V and have OVP function. One step-up DC-DC converter (CH4) regulate a resistoradjustable output up 5V. An adjustable operating frequency (up to 1.4MHz) is utilized to get optimum size, cost, and efficiency. RT9903B is available in VQFN-24L 4x4 package. Each DC-DC converters have independent shutdown inputs. z z z z z z Applications z z z Digital Still Camera ...