A 2μW Three-Axis MEMS-based Accelerometer

This paper describes a prototype acceleration sensor that enables chronic motion sensing in battery powered applications. The design facilitates inertial measurement with minimal area, power penalty, and routing concerns by converting three axes of acceleration into three independent analog output channels in a single package. The sensor includes on-chip memory to store trim codes during production, and built-in electrostatic self-test to enable complete verification of the accelerometer signal chain at any time. The total supply requirement is 1 μA from a 1.8 V supply, with a noise floor of 1 mG/rtHz. A figure of merit, the noise efficiency (NE), is introduced for comparison of sense interface performance for noise and power. Applying this metric, we demonstrate that the sensor architecture explored in this paper represents the state-of-the-art for both absolute power dissipation and power efficiency with respect to the noise floor.