Digital and analogue considerations for 24-bit performance from a PWM DAC

Pushing the performance of PWM converters beyond the 20-bit mark is less than straightforward, partly because of the inherent nonlinearity of PWM. This is a mathematical consequence of the nature of PWM, and can be compensated digitally. As this topic has been extensively discussed , the authors give a rather compressed review. In contrast, the design of the analogue interface, where the stream of conceptual 1s and 0s is converted to a waveform having precise levels and timings before being low-pass filtered, is still very much a live issue, and this paper is being given partly with the intent of soliciting input from the readers knowledgeable in the art