Design of 1.94-GHz CMOS Noise-Cancellation VCO

Through the understanding of various phase-noise mechanisms and sources in an LC voltage-controlled oscillator (VCO), a noise-cancellation technique has been proposed earlier. The 2-GHz CMOS noise-cancellation VCO, fabricated in 0.35-μm CMOS, has achieved an overall phase-noise reduction of 10 dB and phase noise of -121.6 dBc/Hz @ 500-kHz offset. The VCO core consumes 2.8 mA under 2.4-V supply and occupies an area of 0.7 mm × 0.8 mm. It achieves a figure-of-merit of -186 dBc/Hz. In this paper, we will examine the design methodology of this proposed noise-cancellation VCO in detail.