Force-balanced sensing is used in capacitive accelerometers to improve
the linearity. the whole point is to used negative feedback (e.g.,
electrostatic force) to decrease the displacement of the proof mass.
My question is: why not simply increase the spring constant? e.g., by
making stiffer supporting beams of the proof mass? My guess is that
the spring constant is not easy to control so there might be
nonuniformity problem. But this argument does not convince me 100%.
the force-balanced sensing was employed in ADXL50.
but I didn't find it in ADXL150's data sheet. did AD abandon
force-balanced sensing?
any input will be highly appreciated.

Yong