Noise contributors in a 7.2 GHz low-power VCO with automatic amplitude control

In this paper, the major noise sources in a VCO with automatic amplitude control (AAC) circuit, fabricated in a commercial CMOS deep n-well 0.18 /spl mu/m technology with access to the body of NMOS transistors, is described. The analysis shows that there is an optimal point where the noise due to the AAC is minimal and equal to that of a VCO with no AAC. The oscillator consumes 4.32 mW at 1.8 V, has a tuning range of 410 MHz and a phase noise level of -108 dBc/Hz at 1 MHz from a 7.2 GHz carrier.