A Low-Power, Wide-Bandwidth, Three-Axis MEMS Accelerometer ASIC Using Beyond-Resonant-Frequency Sensing
James P. Lin, Long Pham, Ran Tao, A. Gutmann, Shanglin Guo, Adam Cywar, Adam Spirer, Johan Mansson, Khiem Nguyen
Abstract
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- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> CMOS technology and is packaged with two three-axis MEMS sensors achieving a 4-kHz, 25- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{g} / \surd $ </tex-math></inline-formula> Hz, ±8-g accelerometer consuming 375 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{A}$ </tex-math></inline-formula> and an 8-kHz, 59- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{g} / \surd $ </tex-math></inline-formula> Hz, ±30-g accelerometer consuming 550 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{A}$ </tex-math></inline-formula> . 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.