A low cost monolithic accelerometer

The ADXL50, a complete scaled and temperature-compensated surface micromachined accelerometer with an output voltage proportional to acceleration with full-scale measurement range of +or-50 g and unpowered shock survival at 2000 g, is designed for crash detection in second-generation automotive air bag systems. A digitally activated self-test electrostatically deflects a functional beam so that a -50-g acceleration is indicated. An uncommitted amplifier, with rail-to-rail output range, allows rescaling and offsetting of the raw output signal. Capacitors can be introduced in the gain network surrounding the uncommitted amplifier so that two poles of low-pass filters are possible without the addition of off-chip active circuitry. Measured performance results for the ADXL50 are summarized.<
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