A high-performance accelerometer with a fifth-order sigma–delta modulator

Yufeng Dong, Michael Kraft, Carsten Gollasch, William Redman-White
2005 Journal of Micromechanics and Microengineering  
To verify the effectiveness of a higher order electromechanical sigma-delta modulator ( M), a micromachined accelerometer is fabricated. The in-plane sensor with fully differential structure has a mechanical noise floor below 1 µg Hz −1/2 , static sensitivity 16 pF g −1 and resonant frequency 325 Hz. FEM analyses are performed to verify these key parameters. The silicon-on-glass sensor is fabricated by deep reactive ion etching (DRIE) and anodic bonding. Compared with a second-order
more » ... d-order electromechanical M, which only uses the sensing element as a loop filter, here it is cascaded with additional electronic integrators to form a fifth-order electromechanical M, which leads to better signal to quantization noise ratio (SQNR). This novel approach is analysed and system level simulations are presented. A printed circuit board (PCB) prototype of this high-order M loop was built and tested. The experimental data agree well with the simulation results.
doi:10.1088/0960-1317/15/7/004 fatcat:nz4bcgo7yjbrfbrrgnxpbu5ota