LIS2HH12 Noise Information

[cn2]

Posted on August 16, 2016 at 17:37

Hi,

I've a design based on LIS344ALH where the noise level is a very sensitive parameter since I need to measure signals in the mg range. I would like to move to a full digital component and I'm looking to the LIS2HH12. Unfortunetely, the datasheet doesn't contain any information about noise. Can I get this information? Another question: almost all accelerometer's datasheets talk about the mechanical noise only in �g/sqrt(Hz), but without giving a full noise figure taking into account the acquisition chain. For analog accelerometers, could I consider that I can map the value for mechanical noise to an electrical noise value using the sensitivity? For digital accelerometers, could Iconsider that I can map the value for mechanical noise to an digital noise (in LSB) value using the sensitivity? Thanks! #accelerometer-noise

[Miroslav BATEK]

Posted on August 17, 2016 at 15:33

Typical value of acceleration noise for LIS2HH12 is 1.4mg(RMS) at ODR=100Hz, BW=50Hz, FS

±

8.0g

The figure in datasheet is total noise of the whole chain (MEMS element, amplifiers, filters, ADC, …).

Best regards

Miroslav

[cn2]

Posted on August 17, 2016 at 18:31

Thanks!

If the BW is 50 Hz, that means a noise spectral density of about 197µg/sqrt(Hz). For +-8g range, the LSB is 0.244mg, which means the RMS noise is about 6 LSBs. For my application, I'll use the +-2g range with ODR 10 Hz and BW 50Hz. Do you have a value for RMS noise for this range? Best Regards, Christophe

[Miroslav BATEK]

Posted on August 24, 2016 at 17:13

Unfortunately, we can’t share other noise values on the public forum.

You can contact your local sales representative.

But please be aware that for ODR = 10Hz the anti-aliasing filter is fixed to 400Hz, so there could be aliasing effect. 

I would recommend to use ODR = 100 Hz, set the analog anti-aliasing filter cutoff frequency to 50Hz and then use digital low-pass filter.

Best regards

Miroslav

[alessio31183]

Posted on August 15, 2017 at 11:56

Niclaes, are you using it for tilt measurement, right?

Because I'm moving on this accelerometer right now after trying different analogic solution (LIS344, KXR94 and ADXL203).

Currently I'm writing the driver.

Do you have any suggestion about the register settings?

If you wish I can share with you my experience on tilt measurement.

Thanks

[Miroslav BATEK]

Posted on August 15, 2017 at 12:03

You can also consider usage of 

http://www.st.com/content/st_com/en/products/mems-and-sensors/accelerometers/lis3dhh.html

 which is very low noise accelerometer.

[alessio31183]

Posted on August 15, 2017 at 12:25

It seems to be a brand new accelerometer. Isn't it?

Not mentioneted in

http://www.st.com/content/st_com/en/products/mems-and-sensors/accelerometers.html?querycriteria=productId=SC444

 

[Miroslav BATEK]

Posted on August 15, 2017 at 14:14

Indeed it is quite new device.

For you information, please be aware that the LIS3DHH has only SPI interface.