本文基于SMIC 0.35μm标准CMOS工艺设计了一款高精度、宽温度补偿范围的温度补偿晶体振荡器(TCXO)芯片.利用函数发生电路产生符合f-T关系的五次多项式电压,电路产生电压与f-T特性表达式中的对应项相符合,求和电路可对各项系数进行单独调整.电路参数的调整范围使得大部分AT切石英晶体均适用于本设计.测试结果表明,在-40℃~105℃的温度范围内,TCXO频率稳定性达到±0.6ppm.
This paper presents a temperature compensated crystal oscillator(TCXO) chip with high accuracy and wide compensation temperature range,using SMIC 0.35μm standard CMOS process.The function generation circuit can generate voltage according with the five-ordered polynomial of crystal f-T characteristics,each part of the circuit can generate corresponding voltage of each term of the polynomial,and the adder circuit can adjust the coefficient of each term separately.The adjusting range of the circuit makes most a majority of AT cut crystals can be used in this design.The test results show that the frequency stability of TCXO can reach ±0.6ppm over the temperature range-40℃~105℃.