A Low Power, Wide Band Robust Startup Class C DCO with High Resolution

A robust starting complementary Class C DCO with low phase noise and low power consumption is designed by 40 nm process. The frequency modulation accuracy of the DCO is improved by using a mismatched capacitor pair structure on the inverted PMOS varactor. The tuning bank of this DCO consists of a 6-bit band-tuning capacitor array, a 4-bit coarse-tuning capacitor array, a 4-bit medium-tuning capacitor array, and a 4-bit fine-tuning capacitor array, which can obtain a frequency tuning range of 9.6 GHz to 10.5 GHz; and a two-bit PVT capacitor array is also used to cope with the variation of different process angles. The robust start-up circuit mainly consists of an amplitude detection circuit and a comparator to control the gate voltage of the cross-coupled NMOS transistor. Simulation results show that the DCO has a minimum tuning accuracy of 4.95 kHz, a phase noise of −114.114dBc/Hz@1MHz, and a power consumption of 10.02mW at a frequency of 9.6 GHz with a supply voltage of 1.8V. The FOM value is 183.75.