Comparative Studies of Transistors- and Capacitors-Coupled QVCOs

Abstract

The comparative studies of realizing quadrature voltage-controlled oscillator (QVCO) with MOS transistors and capacitors are presented in this paper. The supply voltage, power consumption, chip area, phase accuracy, phase noise, starting time and frequency tuning range of the two kinds of QVCOs are compared. The two kinds of QVCOs are simulated with GlobalFoundries’ 0.18 μm CMOS RF process, and the Cadence IC Design Tools post-layout simulation results demonstrate that the MOS transistors-coupled QVCO has a low supply voltage, low power consumption and improved phase accuracy; the capacitors-coupled QVCO has low phase noise and short starting time; the chip area and other parameters of the two kinds of QVCOs are the same. The two kinds of QVCOs satisfy the average requirements of modern RF transceivers, so the MOS transistors-coupled QVCO is suitable for low-voltage, low-power-consumption and strict accurate phase requirement transceivers.