Fully-integrated low phase noise bipolar differential VCOs at 2.9 and 4.4 GHz

Two low phase noise voltage controlled oscillators (VCOs) are described. The VCOs are implemented at 2.9 GHz and at 4.4 GHz. The differential VCOs employ monolithic centre-tapped inductors. The core power consumption is 3.5 mA and 4 mA for the 2.8 GHz and 4.4 GHz designs respectively. All VCOs are implemented in a f
T
=25 GHz bipolar process. The measured divided phase noise at 1 GHz is -104 dBc/Hz for the 2.8 GHz design and -101 dBc/Hz for the 4.4 GHz design, both at 100 kHz offset from the carrier. The measured tuning range is 10% for the 2.9 GHz VCO and 6% for the 4.4 GHz VCO.