This is a mixed-signal model of a MEMS accelerometer using a digital feedback controller to limit the displacement of the silicon beams. The technique, which is related to Sigma-Delta A/D converters, is due to Mark Lemkin (Ph.D. thesis, 1997, UC Berkeley). The accelerometer is modeled as a second order differential system. The acceleration is sampled, filtered, and fed back to produce a countering electrostatic force.