DIGITAL-TO-ANALOG CONVERTERS
Converting a digital word to a proportional analog value is a necessary task in counter and parallel types of A/D converters, and is useful for digitally generating analog control signals as well. The D/A converter performs this task. One common device used .to turn a word into a voltage is a precision resistor network driven by electronic switches controlled by each bit in the input word. Each bit of the input word contributes a current proportional to its binary weight to a common line. Figure 5-21 (a) I shows the weighted-current-source D/A converter. A final output amplifier with resistive feedback converts the current to a proportional voltage. This D/A conversion method is fast and accurate.