An on-chip signal conditioning delta-sigma ADC for micro-mechanical gyroscope applications

A configurable Delta-Sigma ADC with on-chip signal conditioning is presented for low frequency, low level micro-mechanical gyroscopes in this paper. A differential input programmable gain front end (PGA) varying from 1 to 128 allows the reception of weak voltage signals directly from analog sensors. A pseudo SPI interface is compatible for microcontroller or DSP based system. Gain settings, signal polarity, channel selection and output data rate from 10Hz to 1kHz can be configured from the control registers by SPI three-wire operation. Using charge balancing and switched capacitor techniques, the presented Delta-Sigma ADC achieves 20 bits of resolution with the sampling clock of 19.5kHz, occupying only 2.9mm ² in 0.35μm CMOS technology. It consumes 5.0mW with the supply voltage of 5V.