A tunable VCO for multistandard mobile receiver

This paper presents a tunable CMOS voltage controlled oscillator (VCO) used to generate 1.8 GHz, 3.6 GHz and 4.2 GHz frequencies for multistandard mobile receiver. The switch architecture is used to combine three VCO´s to get a better phase noise performance tunable VCO. The architecture is able to select the operating frequency based on a control signal. The VCO´s are independently designed with the view of switch architecture combination, so the phase noise performance of this architecture is well below the specification of GSM and WCDMA standards.