A comparative analysis of differential LC VCOs with different tank structures in InGaP/GaAs HBT technology

InGaP/GaAs HBT differential LC VCOs designed with low current consumption and low phase noise performance are presented here. To this end, the two types of oscillator are compared using symmetric and asymmetric inductors. The VCO with symmetric tank structure is 160 MHz of the output frequency range and -12.06 dBm of the output power at 1.66 GHz. Furthermore, the phase noise of this VCO is -73.9 dBc/Hz at 10 kHz and -113.9 dBc/Hz at 1 MHz offset frequencies. This VCO is designed within a total chip area of 0.9 × 0.9 mm². Also, the VCO with asymmetric tank structure is 260 MHz of the output frequency range and -12.36 dBm of the output power at 1.46 GHz. Furthermore, the phase noise of this VCO is -83.3 dBc/Hz at 10kHz and -123.09 dBc/Hz at 1 MHz offset frequencies. This VCO is designed within a total chip area of 0.85 × 0.9 mm².