Design of a wideband and low phase noise LC VCO

In this paper, a 3.18∼4.258GHz wideband and low phase noise LC VCO is proposed. Three binary-weighted switching capacitors are exploited to expand the bandwidth; On-chip LDO is utilized to suppress noise from power supply. Symmetrical noise filtering technique is used to suppress thermal noise from tail current and parasitic resistors of bonding wires. The circuit is implemented with 0.13µm RF CMOS process. The frequency tuning range is from 3.18GHz to 4.258GHz and phase noise is −120dBc/Hz at IMHz offset from 4.258GHz carrier. The Figure of Merit (FOM) is −181dB/Hz and maximum power consumption is 12.5mW.