A MEMS Microphone ROIC Based on a Dual Cross-Sampling Delta-Sigma ADC

A dual cross-sampling Delta-Sigma ADC can effectively replace the programmable gain amplifier commonly used in the readout circuit for a MEMS microphone read-out integrated circuit. Further, it provides a good alternative to triple-sampling ADCs. The input voltage can be multiplied by cross-sampling while the DAC cap size also reduces to half by also using cross-sampling. This readout circuit, fabricated in a
$0.18\ \mu m$
CMOS process, is verified by simulation an A-weighted SNR of 72.7 dBA at −38 dBV