A Ku-Band 195.3 dB Peak FoM LCVCO using Bulk-CMOS high-Q Inductor

A peak FoM Ku-band LCVCO designed in a high resistivity 130nm bulk-CMOS process is presented. It is found that the center-tapped inductor with two top-level thick metals on a high resistivity substrate significantly improves the oscillator phase noise. The prototype uses PMOS cross-coupled pair with voltage biasing through the inductor to minimize noise from the bias resistor. The phase noise mechanism of the center-tapped inductor is analyzed, and an optimum inductor and varactor are selected to lessen phase noise and improve the tuning range respectively. This is demonstrated by the post-layout simulation results. VCO provides a wide tuning range from 15.6 to 16.6GHz and excellent phase noise of −120.56 dBc/Hz at 1 MHz offset when operating at 16.6GHz. The VCO core uses 5.1mA of current from a 1.8V supply and attains a figure of merit of 195.3dB. The peak FoM is achieved without using any tail filters. The designed LCVCO has a compact core size of $0.12mm^{2}$ only.