The initial statement was: "lowest bits of a D/A converter are the most non-linear. By avoiding them you might get a more accurate waveform overall." You can o

The initial statement was: "lowest bits of a D/A converter are the most non-linear. By avoiding them you might get a more accurate waveform overall." You can of course apply dithering to any signal to mask quantization noise. It's just that a perfect N-bit DAC will require less dithering to mask its quantization distortion/noise than a non-perfect/not-quite-linear N-bit DAC which again will introduce less quantization distortion/noise than the (N-k) bit DAC. In fact, you could say that a N-bit DAC is just "perfect reproduction" plus a non-linearity that amounts to the step-width of 1-LSB, e.g. it's resolution. And a 24-bit DAC that unfortunately is off by 8 LSB (2^3) along its 0...2^N-1 to 0V..Uref curve is still as good or better as a 21-bit DAC (24bit-3bit) in reproducing a waveform, and still better than a 16 bit DAC. A graphical representation of this is commonly found in datasheets and called "integrated non-linearity."