CMOS RF: (Still) no longer an oxymoron (Invited)

As CMOS continues to evolve along predicted trajectories, its suitability for RF applications only improves. Peak device f(T) is similar to 40GHz for 0.25 mu m technology and should double roughly every three years if established trends continue. The growing number of interconnect layers benefits passive components as well, such as lateral flux (e.g., fractal) capacitors, accumulation-mode varactors, and shielded Inductors and transformers. Coplanar waveguides of reasonable quality are enabled also, and were recently used in a distributed amplifier with a 23GHz unity-gain frequency, and in a 17GHz distributed oscillator. Device F-min is well under 0.5dB at 1-2GHz, allowing practical LNA NFs in the similar to 1dB range on <10mW of power, while new insights into device noise scaling have eased concerns about hot carrier noise enhancement. Exploitation of a new phase noise theory has allowed a 1.8GHz oscillator to exhibit under -121 dBc/Hz phase noise @600kHz offset, with on-chip spiral inductors and 6mW of power, by using symmetry to suppress the effect of 1/f device noise. The 17GHz distributed oscillator also achieves a phase noise better than -110 dBc/Hz @1MHz on 52mW of power. These developments have most recently resulted in a 0.25 mu m 5GHz LNA/mixer/synthesizer that exhibits 5dB overall NF and -2dBm IIP3 on 45mW of power.