The DS8973 is a 9-digit driver designed to operate from 3-cell battery supplies Each driver will sink 100 mA to less than 0 7V when driven by only 0 1 mA Each input is blocked by diodes so that the input can be driven below ground with virtually no current drain This is especially important in calculator systems employing a DC-to-DC converter on the negative side of the battery If the converter were on the positive side of the battery the converter would have to handle all of the display current as well as the MOS calculator chip current But if it is on the negative side it only has