Built-In Self-Test for Capacitive MEMS Using a Charge Control Technique

A new Built-in Self-Test (BIST) method for capacitive Micro-Electrical-Mechanical System (MEMS) devices using charge-control method has been developed in which the Device Under Test (DUT) is stimulated through current sources. The DUT output signals are first converted to time domain intervals and then measured through a precision Time-to-Digital converter (TDC). The proposed BIST scheme supports self-calibration and produces robust results under process, supply and temperature variations. Simulation results indicate that this method can successfully detect minor structural defects altering the MEMS nominal capacitance by 70af.