A High-Stability Crystal Oscillator with a Controllable Oscillation Amplitude

Crystal oscillator (CO), essential for providing high-precision clock references in electronic systems, typically employ the Pierce structure for easy integration into chips. thus highlighting the importance of their reliability and stability. However, Excessive output signal amplitude may cause nonlinear distortion and nonlinear distortion can lead to electromagnetic interference, shorten the lifespan of the quartz crystal, and increase the startup time of circuits. Therefore, effectively controlling the oscillation amplitude is crucial. This paper presents an amplitude control circuit. By processing the output signal of the CO, this circuit adjusts the size of the current source in the main oscillation circuit, thereby affecting the state of the MOSFET and consequently controlling the output signal. The method includes a system for adjusting negative feedback, aiming to mitigate the detrimental effects of excessive amplitude. Simulation results demonstrate that this amplitude control circuit successfully fulfills its intended performance.