A multi-mode SC audio ΣΔ Modulator for MEMS microphones with reconfigurable power consumption, noise-shaping order, and DR

Recent Trends in Structures and Interfaces of MEMS Transducers for Audio Applications: A Review

“…Σ∆ modulators can be classified into two main categories: discrete-time Σ∆ modulators and continuous-time Σ∆ modulators. Discrete-time Σ∆ modulators operate on signals that are sampled at discrete time intervals and are processed digitally; these modulators typically include an ADC that samples the input signal at a high frequency, followed by a digital filter and a digital-to-analog converter (DAC) [102,103]. In continuous-time Σ∆ modulators, the input signal is sampled continuously and processed in the analog domain; it is constantly compared to a reference voltage, determining a sequence of decisions corresponding to a bitstream.…”

The Evolution of Integrated Interfaces for MEMS Microphones

“…The third design example belongs to the new generation of MEMS microphone interface circuits. This interface circuit is based on a reconfigurable MASH 2-2 DT modulator, which can efficiently target different functions and/or applications, as discussed in Section 1 [ 22 , 24 ]. The reconfigurable DT modulator can operate in different modes depending on the target function or application.…”

“…Then, as soon as the input signal vanishes, the system has to return in stand-by mode. For instance, in always running applications, the bandwidth and requirements are typically relaxed (e.g., 4-kHz bandwidth and dB), but power consumption has to be extremely low [ 14 , 15 , 16 ], whereas, in Hi-Fi applications, the required bandwidth is 20 kHz and the has to be larger than 90–100 dB, but a relatively high (e.g., around 1 mW) power consumption can be tolerated [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ].…”