GENERAL DESCRIPTION
The LM2797/98 switched capacitor step-down DC/DC converters efficiently produce a 120mA regulated low-voltage rail from a 2.6V to 5.5V input. Fixed output voltage options of 1.5V, 1.8V, and 2.0V are available. The LM2797/98 uses multiple fractional gain configurations to maximize conversion efficiency over the entire input voltage and output current ranges. Also contributing to high overall efficiency is the extremely low supply current of the LM2797/98: 35µA operating unloaded and 0.1µA in shutdown. FEATURES
of the LM2797/98 include input voltage and output voltage monitoring. Pin BATOK provides battery monitoring by indicating when the input voltage is above 2.85V (typ.). Pin POK verifies that the output voltage is not more than 5% (typ.) below the nominal output voltage of the part. The optimal external component requirements of the LM2797/98 solution minimize size and cost, making the part ideal for Li-Ion and other battery powered designs. Two 1µF flying capacitors and two 10µF bypass capacitors are all that is required, and no inductors are needed.
National Semiconductor
