A Switchless Dual-core Triple-Mode VCO Achieving 7.1-to-15.7 GHz Frequency Tuning Range and a 202.1 dBc/Hz Peak FoM at 3.7 Kelvin

We reported a dual-core triple-mode voltage-controlled oscillator (VCO) with low power consumption and large frequency tuning range (FTR). We proposed using only magnetic and inductive tuning elements for resonance splitting to construct the VCO’s triple-mode LC tank, which avoids the FTR sacrifice when using a conventional capacitive tuning element to construct the multi-mode tank. To reduce the power consumption of the negative trans-conductance (-GM) cells in the multicore multi-mode VCO, we proposed a structure that provides a triple oscillating mode with only two -GM cores. To overcome the deterioration of phase noise (PN) due to the switch-on resistances, we introduced a switching -GM technique for mode selection without using the MOSFET switches. The wideband VCO was specifically designed for cryogenic operation, utilizing a 28 nm CMOS technology. The measured results demonstrate an FTR of 7.1-15.7 GHz and a peak FoM of 202.1 dBc/Hz at 3.7 Kelvin.