A new oscillator with ultra low phase noise and high output swing

In this paper, a new voltage controlled oscillator (VCO) in a 0.18um CMOS process is proposed, which presents a high voltage swing and low phase noise. This new method offers better specifications with respect to traditional solutions which require higher current dissipation for increasing output voltage swing. The proposed circuit is capable of extra oscillation amplitude without increasing the current level taking advantages of tail current elimination and topology optimization. Simulation results at 2.5GHz with an offset frequency of 1MHz and 3MHz shows a phase noise of about -127.3dB/Hz and -137dBc/Hz, respectively with 1.4mA from 1.8V supply. Also, the Monte Carlo simulation results illustrate that the proposed circuit is very promising to process variations.