A low-power, second-order Delta/Sigma modulator using a single class-AB op-amp for voice-band applications
The design of a power-efficient second-order Delta/Sigma modulator for voice-band is presented. At system level, a new single-loop, single-stage modulator is proposed. The modulator employs only one class-AB op-amp to realize a second-order noise shaping for voice-band applications. The modulator is designed in a 0.25 mu m standard CMOS process, and exhibits 86 dB dynamic range (DR) for a 4 kHz voice-bandwidth. The proposed modulator consumes 125 mu W from a 2.5 V supply.
delta/sigma modulator class-ab op-amp low power voice band application