Wideband VCO with Simultaneous Switching of Frequency Band, Active Core and Varactor Size

As the tuning range of integrated LC VCOs increases, it becomes difficult to co-design the active negative resistance core and the varactor optimally for the complete frequency range. The VCO presented here solves this by adjusting the negative resistance with a switched active core. Also the VCO gain variations are counteracted by employing an analog varactor that can change in size. The implementation in 0.13mum CMOS shows a tuning range from 3.1 to 5.2 GHz, with a power consumption varying accordingly from 2.1 to 7.7 mA from a 1.2V supply. The measured phase noise is -118 dBc at 1 MHz from a 4-GHz carrier