A low phase noise CMOS quadrature VCO is presented. A transformer resonator coupling is analyzed. It is founded that the coupled resonator has high frequency selectivity. The Q factor of a coupled resonator is (1+k) times higher than a single LC resonator. This enhancement leads to low phase noise and low power consumption of a VCO. The VCO is implemented using 0.18 μm CMOS technology. Two VCOs are linked to generate I-Q signals by the direct current modulation method. The VCO shows low phase noise performances of -110 and -117 dBc/Hz at the offset frequencies of 600 kHz and 1 MHz respectively. The oscillation frequency is 8 GHz. The tuning range of 250 MHz is achieved with the control voltage from 0 to 1 V. The VCO draws 8 mA in core circuits with 3 V supply.
|Number of pages||4|
|Publication status||Published - 2003|
|Event||2003 IEEE Radio Frequency Integrated Circuits (RFIC) Symposium - Philadelphia, PA, United States|
Duration: 2003 Jun 8 → 2003 Jun 10
|Other||2003 IEEE Radio Frequency Integrated Circuits (RFIC) Symposium|
|Period||03/6/8 → 03/6/10|
All Science Journal Classification (ASJC) codes