A High-Resolution Accelerometer With Electrostatic Damping and Improved Supply Sensitivity Mikail Yücetaş, Student Member , IEEE, Mika Pulkkinen , Student Member , IEEE, Antti Kalanti, Jarno Salomaa, Student Member , IEEE

Abstract

In this paper, a charge-balancing acce lerometer is presented. A hybrid interface to pology is utilised to achieve high resolution, high linearity and low power supply sensitivity. The accelerometer consists of a micromechan ical sensor element, a self-balancing bridge (SBB) open -loop readout, AC force feedback and ADC. The SBB converts acceleration to ratiometric voltage. The ratiometric output of the SBB is converted to the digital domain by the ADC. In order to achieve high resolution, a micromechanical sensor elemen t with a high quality factor, Q, is utilised. The AC force feedback is us ed for damping the high Q to get a low settling time. The sensor interface is fabricated in a standard 0.35 m CMOS process. The fabricated chip has an area of 6.66 mm and consumes 1 mA at a n ominal supply voltage of 3.6 V. The sensor has a maximum DC nonlinearity of 1.3% over the commercial temperature range with an input range of 1.15 g. The noise floor of the sensor is around 2 and the signal bandwidth is 200 Hz. The bias instability is 13 ga n dt h e sensor gain variation is less than 5% in the 3–3.6 V supply range.