Design of an electronic oscillator for biosensing applications based on a MEMS resonator

Resonant mass sensors (i.e. microbalances) are commonly used in chemical and biochemical sensing, and their MEMS counterparts, based on MEMS resonators, are actively investigated. In this work, we present the design of an integrated electronic oscillator, based on general purpose CMOS operational amplifiers (op-amps) and conceived to operate with a magnetically actuated MEMS resonator fabricated on the same chip as the op-amps. After a description of the resonator and op-amp structure and characteristics, a two-stage, positive feedback oscillator topology is presented. The simulated behavior of the oscillator is presented and discussed, and the temperature stability of the oscillator output frequency is analyzed.