Kerry Wong writes:
One way to extend the resolution of a digital-to-analog converter (DAC) is by employing a sigma-delta converter in software. The main disadvantage of such approach is the slow speed. Alternatively, we can use some extra hardware to extend the usable resolution of a DAC. In this post, I will illustrate one such method to extend an 8-bit DAC to 16 bits using a digital potentiometer.
So why do we want to extend the resolution of a DAC at the first place? Well, one of the key reasons is to lower cost. A 8-bit DAC usually costs less than a dollar, whereas a 16-bit DAC can easily cost ten to twenty times more. Fortunately, with the help of a potentiometer we can make a high resolution DAC out of a low resolution one.