A Tunable-Gain Transimpedance Amplifier for CMOS-MEMS Resonators Characterization

Area of Science:

• * Electrical Engineering
• * Materials Science
• * Microtechnology

Background:

• * CMOS-MEMS resonators offer miniaturization and on-chip integration.
• * Standard CMOS fabrication limits MEMS electromechanical performance and necessitates complex readout circuits.

Purpose of the Study:

• * To present a transimpedance amplifier (TIA) designed for CMOS-MEMS resonators.
• * To demonstrate a TIA fabricated with commercial 0.35-µm CMOS technology for driving and sensing resonators up to 50 MHz.
• * To enable accurate characterization and co-design of MEMS-CMOS integrated systems.

Main Methods:

• * Fabrication of a TIA using a 0.35-µm CMOS process.
• * Integration and characterization of the TIA with three types of CMOS-MEMS resonators.
• * Measurement of TIA performance metrics including transimpedance gain, noise, and power consumption.

Main Results:

• * Achieved tunable transimpedance gain from 112 dB to 121 dB.
• * Demonstrated low output voltage noise (225 nV/Hz^1/2) and input-referred current noise (192 fA/Hz^1/2) at 10 MHz.
• * Exhibited power consumption below 1 mW and an open-loop gain independent of parasitic input capacitance.

Conclusions:

• * The developed TIA effectively drives and senses CMOS-MEMS resonators up to 50 MHz.
• * The TIA's performance advantages, including noise and gain stability, facilitate accurate MEMS characterization.
• * This work enables improved MEMS-CMOS circuitry co-design for advanced microelectromechanical systems.