Study of oscillation characteristics for quartz crystal oscillators based on equivalent multi-physics model

Abstract

In recent years, high-performance quartz-crystal oscillators (XOs) for integrated circuits have been receiving considerable attention due to their featuring low voltage and high-frequency stability. However, recent studies tend to focus solely on the impact of temperature as a single factor on crystal oscillator circuits, overlooking the circuit structure of the crystal oscillator itself. In this paper, a novel four-parameter crystal model of XOs is detailed demonstrated, and analyzed to interpret typical XO oscillation characteristics at room temperature. The relationship between the RLC circuit and the oscillation was investigated. Meanwhile, the study delves into the various factors that influence oscillation behavior, paving the way for a comprehensive understanding of XOs' performance characteristics. temperature sweep simulations were induced to verify the theory and found that the parameter drift and thermal perturbation are close to the theory we proposed, which can be applied in temperature-compatible XOs. The significance of this study lies not only in its contribution to the design and implementation of compact footprint XOs in the oscillator circuit platform but also in its provision of experimental evidence for fabricating wide temperature range compensated XO devices. The results show that the capacitance in the equivalent model of a crystal oscillator plays a dominant role in shaping the output waveform and exhibits relatively good temperature stability characteristics and serve as a valuable resource for engineers and researchers working on improving the performance and reliability of XOs, ultimately enabling the development of more advanced and efficient integrated circuits.