5-GHz g<inf>m</inf>-boosted transformer cross-coupled current-reused colpitts VCO

A low‐phase‐noise and low‐power CMOS colpitts VCO using Gm boosting and capacitance switching techniques

“…In other words, the phase noise of VCOs can apparently degrade selectivity and sensitivity. The paper recently focused on low‐noise and low power LC‐VCO, 1 but other papers did not show great performances in their VCO designs 2‐4 . A G m ‐boosting Colpitts VCO, which was used to increase output power and to reduce phase noise simultaneously, was found in Reference 2.…”

“…A G m ‐boosting Colpitts VCO, which was used to increase output power and to reduce phase noise simultaneously, was found in Reference 2. The Q ‐factors of the transformer‐based tank were improved in References 3,4, but the improvement of the measured phase noise and power consumption were not significant. According to Reference 5, the dual‐core and wideband VCO with concentric 8‐shaped coils was immune to stray magnetic fields, but its penalty was lower quality factor.…”