# Is IMU sensitivity always equal to FS / resolution?

I'm in the process of evaluating MEMS IMUs for a new design.

According to this post, if a Gyroscope's range is ±250°/s, and its resolution is 16-bit (0-65535), then sensitivity can be calculated as: $\frac{500°/s}{65535LSB}=0.0076\frac{°/s}{LSB}$.

I am looking at the accelerometer on the Bosch BNO055. It has a FS range that is user-selectable between ±2g, ±4g, ±8g, and ±16g. One would assume that you would calculate the sensitivity likewise. i.e. if FS=±2g, and accel is 14-bit, then sensitivity is: $\frac{4g}{16384LSB}=244.14\frac{µg}{LSB}$.

However the datasheet says the sensivity is fixed which is rather confusing. Does this mean no matter what FS you set, it's impossible to see increments of less than 1mg?

Parameter: Sensitivity
Symbol: S
Condition: All FS Values, TA=25°C
Min: -
Typ: 1 LSB/mg
Max: -