A precision low-power PCM channel filter with on-chip power supply regulation

A single chip PCM channel filter with improved overall performance characteristics is described. The most important characteristics are power dissipation, idle channel noise, and power supply rejection. The filter described uses switched capacitor techniques and contains two fifth-order low-pass filters, a 50/60 Hz rejection filter, internal anti-alias filters, and a 600 ohm line driver. The filter is implemented in a two layer NMOS silicon gate technology. Experimental results are presented.