A Dynamic GHz-Band Switching Technique for RF CMOS VCO

A CMOS VCO circuit technique which enables a dynamic GHz-band switching has been described. To get wide band switching, it has been clarified analytically that keeping Q constant is important to configure the circuit. To meet this, an LC VCO circuit which can switch resonant capacitors and inductors simultaneously for switching the band has been suggested. To verify the effect, a dual band VCO circuit has been designed and fabricated by using a 0.13-mum standard CMOS process technology and succeeded in switching the band dynamically from 2 to 4 GHz with keeping 1 MHz offset phase noise of -120 dBc/Hz