ULTRA_LOW_POWER_dc_to_dc_CONVERTER_FOR_PERSONAL_COMMUNICATIONS_PRODUCTS

Published:2009/6/18 2:30:00 Author:May | From:SeekIC

The LTC1174 step-down converter is designed specifically to eliminate noise at audio frequen-cies while maintaining high efficiency at low output currents. This circuit shows a 5-V, 120-mA out-put derived from 5 to 7 NiCad or NiMH cells. Small input and output capacitors that are capable of handling the necessary ripple currents help conserve space. In applications where shutdown is de-sired, this feature is available (otherwise short this pin to Vin).The LTC1174's internal switch, connected between Vin and Vsw is current controlled at a peak of approximately 340 mA. Low peak switch current is one of the key features that allows the LTC1174 to minimize system noise compared to other chips that carry significantly higher peak currents, eas-ing shielding and filtering requirements, and decreasing component stresses. Output current of up to 450 mA is possible with this device by connecting the 1 pgm pin to Vin. This increases the peak current to 600 mA, allowing for a high average output current.



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