A Low-g Three-axis Accelerometer IC

This paper presents a three-axis, low-g accelerometer IC with analog and digital outputs for applications in consumer and mobile markets. This accelerometer is consisted of a sensing element chip and a digital IC, and is packed in a 3mm x 5mm x 0.9mm LGA package. The sensing element integrates three spring-proof mass systems with self test electrodes on a single structure for sensing three-axis motion for operating range of 5 g. The programmable resolution for digital output which offers user to adjust the resolution for different applications; and, nominally, the maximum resolution is as high as 16 Bits. The overall noise floors of the x-, y-, and z-axis are 408 mu g/root Hz, 460 mu g/root Hz, 238 mu g/root Hz, respectively. From the characterization, this accelerometer IC demonstrates high cross-axis sensitivity immunity, high sensitivity, and good linearity for both in-plane and out-of-plane accelerometers that suggests this three-axis accelerometer to be potential for satisfying the needs of current applications to consumer and mobile market.