Some MEMS accelerometers use a switching technology to generate the output signal therefore they may have relevant noise.

Testing system was one of the Innovatorium’s platforms (with data acquisition of 16 bits at up to 1 Msps) and signal processing libraries. Picture from the right shows the density of probability of the resulting signal with inputs connected to the ground. About 27% of the samples have a value in the range of –5…+5uV.

For an ADXL203CE (Analog Devices) as device under test with 0.1uF filtering capacitors on each output the density of probability of the signal under steady state conditions is shown below. About 0.45% of the collected samples are within –5…+5uV. The switching process significantly distorts the theoretical bell shape.