A low power 30 GHz Class-D VCO with common mode resonance in 22 nm FD-SOI

In this paper, we investigate a class-D CMOS VCO (Voltage Controlled Oscillator) at 30 GHz. To prove the concept, the circuit is implemented in 22 nm Fully Depleted Silicon On Insulator (FD-SOI) technology. It features a compact inductor with close coupling distance and a second harmonic common-mode resonance to boost the phase noise performance. The VCO needs a DC power of 2.08 mW from a 0.5 V supply and shows a measured free running phase noise of -116.5 dBc/Hz at 10 MHz offset. Thanks to the compact inductor the proposed VCO only occupies an area of 0.0156 mm(2) and achieves one of the best FoMA, a figure of merit that also takes the VCO core area into account, among the state-of-the-art VCOs around 30 GHz.