ADxRS614: Gyro Null fluctuates

Document created by analog-archivist Employee on Feb 23, 2016
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I am using ADXRS614 gyroscope in one of my projects. I am having trouble with
this sensor and I couldn't find solution for it. The problem is gyro's outputs
swing +-5mV. So adc output changes in stall position at least +-4 Lsb because
of this i can't hold angle position or any other values correctly. Adc and
gyro's Vrefs connected to same source so I eliminated some of errors by using
ratiometric system. Gyro connected as described in pdf and using about 30Hz
Bandwith. Do you have any suggestions to suppress this DC output swing.


The ultimate drift accuracy that you can achieve by calibrating a gyro depends
on several factors

- precision in the measurement of null and sensitivity (e.g. due to noise,
measurement resolution)

- precision/repeatability in the measurement of temperature of the IC.

- non-linearity of the offset vs. temperature and sensitivity vs. temperature
characteristics (how many temperature points are calibrated)

As mentioned in the datasheet using a 3-point calibration technique, it is
possible to calibrate the null and sensitivity drift of the ADXRS614 to an
overall accuracy of nearly 200°/hour. An overall accuracy of 40°/hour or better
is possible using more points. Limiting the bandwidth of the device reduces the
flat-band noise during the calibration process, improving the measurement
accuracy at each calibration point.