A 7.5mW 101dB SNR low-power high-performance audio delta-sigma modulator utilizing opamp sharing technique

A low power and high performance third order delta-sigma modulator for audio applications, fabricated in a 0.18/im CMOS process, is presented. The modulator utilizes a third order noise shaping with only one opamp by using opamp sharing technique. The opamp sharing among three integrator stages is achieved through the optimal operation timing, which makes use of the load capacitance differences between the three integrator stages. The designed modulator achieves 101.1dB signal-to-noise ratio (A-weighted) and 101.5dB dynamic range (A-weighted) with 7.5mW power consumption from a 3.3 V supply.