04-06-2021 05:22 PM
What exactly is meant by the BMI085 having good temperature stability? Because I was comparing the datasheet to that of the BMI270 and the relevant specifications seem not to indicate any difference:
Zero-rate offset drift for both is 0.015 degrees per Kelvin, and sensitivity drift is slightly higher for the BMI085 at 0.03 % per Kelvin vs. 0.02 % per Kelvin for the 270. SO basically, they're the same, with the BMI085 arguably being slightly worse.
We've found the temperature offset adjustment of the 270 to be really problematic and were looking into alternatives. The 085 sounded good but I'm not seeing it in the specs. The next choice would be the BMI260 which I think doesn't attempt to adjust offsets for temperature. This would be preferable as it would not then interfere with our own attempts to calilbrate.
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04-06-2021 07:57 PM
Thanks for your inquiry.
It is true that the TCO of BMI085 and BMI270 gyroscope has the same 0.015dps/K. BMI085's gyro good temperature stability is referring to BMI160's 0.05dps/K. BMI160 is older generation of BMI270 where their gyro is open-loop with long-term bias stability less than 10 degree/hour.
The gyro inside BMI085 (for AR/VR) and BMI088 (for Drone and Robot) is closed-loop gyro, where it has long-term bias stability less than 2 degree/hour. It consumes 5mA current. BMI160/BMI270 gyro consumes less than 1mA current. So if your application needs high temperature stability, then you may consider BMI085 or BMI088.
04-07-2021 09:23 AM
Thanks for the reply but I'm afraid I still don't understand. The long term stability of 2 degrees/hour is good news, but I don't see how it relates to temperature. What exactly is the difference in temperature response between the BMI270 and the BMI08x? Your first paragraph sounds like you're saying it's just good compared to the 160, but no different to the 270? Let's assume for the moment that I'm not concerned about power consumption.
04-07-2021 04:29 PM
Yes, from TCO and TCS point of view the gyro temperature stability of BMI085 and BMI270 is the same.
04-08-2021 09:25 AM
Understood, thanks for the information.