Theoretical analysis of low phase noise design of CMOS VCO

A theoretical analysis on low phase noise of voltage-controlled oscillators (VCOs) based on complementary cross-coupled LC VCO by 0.35-/spl mu/m complementary metal oxide semiconductor technology is demonstrated. From the procedure of optimization steps, the excess noise factor of the amplifier coming from the active device has been determined. The proposed VCO operates at 2 GHz with phase noise of -116 dBc/Hz at offset frequency 600 kHz. The power consumption is 22.62 mW under 3 V bias with 9.1% frequency tuning. The achievement of low phase noise is also matched with prediction by formula in the frequency domain.