Load independent bulk-coupled low power quadrature LC VCO

A novel low voltage bulk-coupled CMOS LC quadrature voltage controlled oscillator (QVCO) implemented in a standard 0.18 um BiCMOS process is presented in this paper. Quadrature signals are achieved by using injection of output signals of independent complementary LC VCOs into body terminal of each cross-coupled pair. Tapped capacitor technique is used to lower phase noise and achieve load independence. The implemented QVCO achieves a measured phase noise of −95.6 dBc/Hz at 50 KHz offset from 6.26 GHz carrier frequency. The total power consumption is 3.2 mW from a 1.2 V supply. The active die area is only 0.3 mm2. The achieved Figure of Merit (FOM) is −192.5 dBc/Hz and FOMA is −197.7 dBc/Hz which are among the best compared to recently published QVCOs.