A design of +/- 0.28ppm temperature-compensated crystal oscillator in a 0.35m CMOS process

摘要

A high-performance temperature-compensated crystal oscillator (TCXO) is presented. This paper proposes a new temperature sensor with a sigma- analog to digital converter, and a voltage-controlled crystal oscillator, respectively, using two sets of independent power supply. The presented TCXO is implemented in a 0.35m 2P3M standard complementary metal-oxide semiconductor process at a power supply of 3.3V, and the total power dissipation is 21mW. Measurement results indicate that the designed TCXO achieves +/- 16ppm output frequency tuning range and 135, -141dBc/Hz phase noise at 1, 10kHz frequency offset, respectively, by using a 40MHz fundamental AT-cut crystal resonator. With the temperature compensation, the frequency deviation is within +/- 0.28ppm over -40 degrees C to 85 degrees C.