Title :
A 300Hz 19b DR capacitive accelerometer based on a versatile front end in a 5th-order ΔΣ loop
Author :
Pastre, Marc ; Kayal, Maher ; Schmid, Hanspeter ; Huber, Alexander ; Zwahlen, Pascal ; Nguyen, Anne-Marie ; Dong, Yufeng
Author_Institution :
STI IEL ELab, EPFL, Lausanne, Switzerland
Abstract :
This paper presents a 5th-order DeltaSigma capacitive accelerometer. The DeltaSigma loop is implemented in mixed signal, the global 5th-order filter having a 2nd-order analog and a 3rd-order digital part. The system can be used with a wide range of sensors, because the mixed-signal front end is programmable. The ASIC developed comprises a voltage-mode preamplifier, two parallel demodulators implementing CDS, and a 7-bit Flash ADC. The latter drives a 3rd-order digital filter, which can be configured for different sensor parameters in order to ensure overall loop stability and optimize the noise performance. With a low-noise MEMS sensor, the system achieves a 19-bit DR and a 16-bit SNR, both over a 300 Hz bandwidth.
Keywords :
accelerometers; capacitive sensors; demodulators; digital filters; microsensors; mixed analogue-digital integrated circuits; preamplifiers; sigma-delta modulation; 2nd-order filter; 3rd-order digital filter; 5th-order DeltaSigma capacitive accelerometer; 5th-order filter; 7-bit Flash ADC; ASIC; DeltaSigma loop; frequency 300 Hz; loop stability; low-noise MEMS sensor; mixed-signal front end; parallel demodulators; voltage-mode preamplifier; Accelerometers; Application specific integrated circuits; Demodulation; Digital filters; Micromechanical devices; Preamplifiers; Sensor systems; Signal to noise ratio; Stability; Voltage;
Conference_Titel :
ESSCIRC, 2009. ESSCIRC '09. Proceedings of
Conference_Location :
Athens
Print_ISBN :
978-1-4244-4354-3
DOI :
10.1109/ESSCIRC.2009.5326033
