An Integrated Force-balanced Capacitive Accelerometer For Low-G Applications

A low-cost monolithic accelerometer which incorporates a surface micromachined polysilicon sensor with bipolar/ MOS interface circuitry on a single chip has been devel oped for a measurement range of ~5g. The accelerometer has a noise floor of 0.6 mgNHz and a shock survival rating of 1000 g. A sensitivity temperature coefficient of ~50 ppm/'C and an offset temperature coefficient of ~5 mg/C have been achieved over the -40 'C to 105 'C automotive temperature range. A wide bandwidth from DC to 4 kHz is adjustable using a single external capacitor. The acceler ometer operates on a single 5 V power supply and con surnes 40 mW of power. It provides an analog output of 200 mV/g and a digitally activated self-test output of -5 g.