A low power low phase noise wide switched tuned band LC VCO for S band applications

This paper deals with the design problems associated to the implementation of low power wide tuning band low phase noise LC VCOs in low cost Si-integrated technologies. For that, a VCO was developed using a low cost 0.35 mum 2-poly 4-metal standard CMOS technology. The VCO uses a radio frequency switched varactor array (RFSVA) in the tank circuit in order to decrease the influence of the varactor tuning input on the oscillator phase noise. The VCO presents a continuous tuning band from 2.76 GHz to 3.36 GHz, a single-ended output power that ranges from -12 dBm to -6 dBm and a phase noise always lower than -117 dBc/Hz at an offset frequency of 1 MHz. Moreover, the two output ports of the VCO present return losses higher than 12.7 dB in the 600 MHz tuning band. The VCO core works with a voltage supply of 1.5 V and has a current consumption of 5 mA and the output buffers draws 18 mA from a 3 V voltage supply.