I`m doing some research on sensors for measuring structural vibrations.
Looking into ADXL355 datasheet I found that its Scale Factor is equal to 3.9 ug/LSB using a Dynamic Range of +-2g . Datasheet also informs the noise density is equal to 25 ug/rt(Hz). However, if we use this noise density with a 1000 Hz BW we find that the resolution of the sensor is Resolution = 25u*rt(1000*pi/2) ~ 1mg.
So, does it make sense using a scale factor 250 times lower than the resolution of the sensor? Am I missing something?
If I used ADXL354 that has 20 ug/rt(Hz) noise density, would I be able to get a better resolution?