Programmable active inductor-based wideband VCO/QVCO design

Programmable wideband voltage-controlled oscillator (VCO) and quadrature VCO (QVCO) circuits which adopt modified gyrator-C-type active inductors with PMOS transistors in the feedback path are presented here. New design equations are derived for an active inductor considering the effects of the parasitic capacitance of PMOS and are used to design a high-Q active inductor. The fabricated VCO and QVCO achieve frequency tuning ranges from 1.85 to 3.66 GHz and 1.55 to 3.61 GHz, respectively. The measured phase noise of VCO and QVCO range from -81.1 to -111.3 dBc/Hz and from -80.1 to -107.7 dBc/Hz at 3 MHz offset, respectively.