A 70dBA-460μW Companding Digital Silicon Microphone with Programmable Acoustic Overload Point and MEMS Asymmetry Robustness

This paper presents a Companding Silicon Microphone System achieving 70dB SNR (A-weighted) measured at 1Pa - 1kHz input signal (-34dBFS digital output level). The combination of inverter-based techniques and a DAC-on-demand approach in the Delta-Sigma ADC helps to reduce the power consumption of the complete product to only 460μW. Robustness against MEMS asymmetries and programmable Acoustic Overload Point (AOP) are included. Developed in a CMOS 130nm technology, the ASIC has an approximated area of 1.1mm2 (including all auxiliary circuits).