关键词: ?晶振电路, 整形电路, 电平移位

Abstract: The equivalent model and performance parameters of quartz crystal are analyzed, and an 8 MHz crystal oscillator circuit based on Pierce oscillator is designed. It mainly includes Pierce circuit, enable control and isolation circuit, bias circuit and shaping and level shift circuit. Aiming at the problem that the digital circuit clock is a square wave and the digital voltage domain is different from the analog voltage domain, a shaping and level shift circuit is designed to shape the sine wave output by the crystal oscillator into a square wave, and it can work in dual voltage domain. Based on HHGRACE 0.11 μm 4P5M CMOS process, using Cadence Spectre to simulate the designed circuit, the results show that when the power supply voltage is 3.3 V, the output frequency of the crystal oscillator circuit is 8 MHz, the start-up time is 0.35 ms, and the output waveform accounts for 49.89% of the air and the operating current is 350 μA.

Key words: crystaloscillator, shapingcircuit, levelshifter