A 5-V single-chip delta-sigma audio A/D converter with 111 dB dynamic range

A 5-V 24-b audio delta-sigma A/D converter has been developed. The single chip integrates stereo delta-sigma modulators, a voltage reference, and a decimation filter. A fourth-order cascaded delta-sigma modulator using a local feedback technique was employed to avoid overload without sacrifice in noise performance. A two-stage decimation filter architecture which reduces digital noise was developed. A new multistage comb filter was used for the first-stage, and a bit-serial finite impulse response (FIR) filter was used for the second stage. The 25.8 mm² chip was fabricated in 0.7-μm CMOS with low threshold MOS devices. Measured results show 111 dB dynamic range and 103 dB peak signal-to-(noise plus distortion)S/(N+D)