A 1-V low phase noise multi-band CMOS voltage controlled oscillator with switched inductors and capacitors

A low voltage multi-band all PMOS VCO was fabricated in a 0.18-μm CMOS process. By using a combination of inductor and capacitor switching, four band (2.4, 2.5, 4.7 and 5 GHz) operation was realized in a single VCO. The VCO with 1-V power supply has phase noises at 1-MHz offset of -126 dBc/Hz at 4.7 GHz and -134 dBc/Hz at 2.4 GHz, respectively. It has the lowest phase noise among the CMOS VCOs presented to date in all the bands. The VCO consumes 4.6 mW for 2.4 and 2.5 GHz, and 6 mW for 4.7 and 5 GHz operations, respectively.