A low-voltage and temperature compensated ring VCO design

A low-voltage, two-stage ring voltage-controlled oscillator (VCO) which can tolerate temperature variation is presented in this paper. Designed using a 0.13 μm CMOS technology, this VCO is capable of operating at 1-V power supply voltage not only for low power consumption, but also to reduce hot-carrier effects and improve reliability and lifetime. It incorporates coarse and fine frequency tuning mainly for tolerance of process variations while achieving small control-voltage-to-frequency gain and enough tuning range of the VCO. Most importantly, a new temperature compensation technique which is suitable for low power supply voltage design is proposed to enable continuous operation of the VCO in variable ambient temperatures environment. Simulations show that with the proposed techniques, the VCO can tolerate process variations, dynamically adapt to different temperatures, and achieve a low temperature sensitivity of 34 ppm/°C over the range from -40°C to 120 °C.