Area comparisons of CMOS voiceband coders in scaled technologies

The author explores alternatives for implementing the analog-to-digital interface with an antialias filter in voiceband telephony application. Since the resolution of the interface is fixed by transmission standards, the goal is to achieve the minimum cost, or area in integrated circuit technology. The chip area implemented in CMOS technology for three distinct approaches is compared: the conventional analog method, the per-channel oversampled method and the multichannel oversampled method. It is found that among the three implementations the per-channel area taken by the multichannel oversampled approach decreases at the fastest rate as technology scales and will take less area than the conventional approach at a minimum feature size of 1.5 mu m and below.<>