Analysis and design of a transimpedance amplifier based front‑end circuit for capacitance measurements

摘要

In this study, transimpedance amplifier based front-end circuits which can be employed to measure small capacitanceswere designed, analyzed and simulated using analog electronic circuit simulator. The front-end circuit converts the currentflowing through the measured capacitance into a modulated voltage value which contains information regardingthe desired capacitance. The frequency-domain, time-domain, stability and noise analyzes were carried out numericallyand in simulation environment using a circuit simulator. The analytical, numerical and simulation results can be used todesign optimized, precise and stable transimpedance amplifiers with low-noise value. The measured capacitance valuewas 10 pF which is low enough to simulate various real-world applications. Three commercially available, off-the-shelfoperational amplifiers with different peripheral passive components were employed for computer based analysis. Thedesigned transimpedance amplifiers are suitable to connect with capacitance extraction circuits which use analog ordigital demodulation techniques.