A 48MHz Temperature Compensated Crystal Oscillator Utilizing Time-Domain Accuracy Boosting Techniques Achieving ±1.4ppm Frequency Stability from -55°C to 115°C

Temperature Compensated Crystal Oscillators (TCXOs) are preferred over traditional XOs due to their capability to significantly reduce temperature’s impact on frequency stability. Adjusting load capacitance ($\mathrm{C}_{\mathrm{L}}$) offers a straightforward and effective compensation method that integrates seamlessly into existing XOs without requiring additional reference sources or loops [1–5]. As depicted in Fig. 1, conventional analog compensation scheme processes temperature information directly in the voltage domain, ensuring a straightforward circuit implementation [4]. However, it faces challenges in compensation precision across process variations and adaptability for crystals with diverse temperature characteristics. In contrast, conventional digital compensation schemes convert temperature signals in a noiseless digital manner but may introduce transient frequency micro-jumps and parasitic spectra, potentially affecting phase noise (PN) due to the discrete-time refreshing and zero-order hold behavior of $\mathrm{C}_{\mathrm{L}}$ [1, 2, 3].