Noise Analysis of Silicon Microgyroscope's Transimpedance Amplifier Interface Circuit

The output-current of silicon microgyroscope is at the level of 10-7A. So the requirements for circuits’ SNR are very high. This paper proposes a method to improve transimpedance amplifier interface circuit’s SNR. First of all, the operating principles of silicon microgyroscope and transimpedance amplifier interface circuit are introduced. Secondly, resistor thermal noise, amplifier’s current and voltage noise are analyzed. Then noise density in a certain frequency range is calculated based on Matlab. Besides, a method to improve SNR is proposed, namely, increasing the value of DC offset resistance. Finally, simulation based on Cadence is operated to verify the method. Simulation results fit well with the theoretical analysis. That means the method to improve the SNR is feasible.