A 4.1–5.2 GHz LC VCO using a vertical solenoid inductor in 0.13 μm digital CMOS

This paper presents a small area LC VCO with an on-chip 3-D solenoid inductor using the 0.13 m digital CMOS process. The on-chip solenoid inductor is vertically constructed by using Metal and Via layers with a horizontal scalability. Compared to a spiral inductor, it has the advantage of occupying a small area and this is due to its 3-D structure. The LC VCO with solenoid inductor is fabricated in 0.13 m process and the die area of solenoid inductor is 0.013 mm2. The measured phase noise is -110.61 dBc/Hz at 1MHz offset when the output frequency is 5.195 GHz. The measured tuning range is about 1.1 GHz. The power consumed from 1.2 V supply, is 13.2 mW.