Modeling and Characterization of a 5.2 GHz VCO for Wireless Communications

This paper describes a 5.2 GHz Voltage-Controlled Oscillator (VCO) as a key component in RF transceivers. The circuit includes a complementary cross - coupled MOSFET as a negative conductance, beside a tank circuit which consists of an optimal on-chip spiral inductor (L), and an accumulation mode MOS varactor (C(V)). A model for phase noise and figure merit is introduced and verified through simulation in a standard 0.13 mu m CMOS process. The VCO core drew a 4.2 mA of current from a 1.2 V power supply and a phase noise of -98.5 dBc/Hz at 1 MHz offset from the 5.2GHz carrier was calculated. The whole performance of the circuit specifically the tuning range was found to be 26%.