A Low-Power, Wide-Bandwidth, Three-Axis MEMS Accelerometer ASIC Using Beyond-Resonant-Frequency Sensing

This article presents a 16-bit wide-bandwidth (BW) high-performance (HP) three-axis micro-electromechanical system (MEMS) accelerometer readout application-specific integrated circuit (ASIC). It is the world’s first accelerometer to use beyond-resonant-frequency sensing technique to extend the BW by digitizing and equalizing the full sensor response including the MEMS sensor resonance. The readout ASIC consists of dual signal paths: three 16-bit HP signal paths to sense frequency-rich signals, such as acoustic or vibration, and one shared 12-bit low-power (LP) signal path to sense temperature and motion simultaneously. The ASIC is fabricated in 0.18- $\mu \text{m}$ CMOS technology and is packaged with two three-axis MEMS sensors achieving a 4-kHz, 25- $\mu \text{g} / \surd $ Hz, ±8-g accelerometer consuming 375 $\mu \text{A}$ and an 8-kHz, 59- $\mu \text{g} / \surd $ Hz, ±30-g accelerometer consuming 550 $\mu \text{A}$ . The proposed technique compensates the transfer function deviation from 4.6 and 8.9 dB to less than ±0.56 and ±0.52 dB in two accelerometer prototypes.