Charge-Controlled Readout and BIST Circuit for MEMS Sensors

In this paper, we present a new readout circuit with an integrated built-in self-test (BIST) structure for capacitive microelectromechanical system (MEMS). In the proposed solution, instead of commonly used voltage control signals to test the device, charge-controlled stimuli are employed to cover a wider range of structural defects. The proposed test solution eliminates the risk of structural collapse in the test phase for gap-varying parallel-plate MEMS devices. Measurement results using a prototype fabricated in TSMC 65-nm CMOS technology indicate that the proposed BIST scheme can successfully detect minor structural defects altering MEMS nominal capacitance.