ISM330 gyro sensitivity mismatch

[Trinh]

Greeting, this is my first ever post on the forum so i hope the topic can be interesting to others.
I was working with the ISM330 gyro, reading the datasheet and i noticed that the gyro rate sensitivity seems to be a bit off. Here is what they mention in the datasheet, when i look at the angular rate sensitivy (let assume we have put a full scale range of 2000 dps) the typical value here is 70 mdps/LSB with the tolerance of +-2%. This value doesnt seem to map all the 16 bit signed integer because if you do the math with 70 mdps/LSB the full scale range is actually 2293 dps not 2000 dps, that's like 14% deviation. I don't really know if its intended like this but it's obviously strange, i have worked on many other gyros previously, let say for example mpu6500 or mpu6050 and they don't seem to have this mismatch issue.
I have looked up the issue and found a blog post of a japanese that also experience this frustration with the ISM330 (https://rofumi.net/gyroscope-ism330dhcx-angle/ ). It's a good read so i recommend people looking into it.
Looking forward to the answer of the sensitivity mismatch.
Best regard, 

Trinh

 

[Federica Bossi]

Hi @Trinh ,

This discrepancy arises because the full-scale range (±2000 dps) defines the maximum measurable angular rate, but the sensitivity is calibrated to a slightly different scale for better accuracy and linearity within the operational range.