A full swing and low power voltage-controlled ring oscillator

This paper presents a full swing and low power Voltage Controlled Ring Oscillator fabricated in a 0.35um CMOS technology. The VCO delay cell utilizes a nmos delay pair to save the power dissipation while degrading the phase noise a little.the proposed VCO has a wide tuning range from 450MHz to 1.15GHz with a good linearity. The phase noise is -106dBc/Hz at 500 KHz offset from the center frequency of 866MHz and it consumes 24.5mW using a 3.3V power supply. The area of VCO is 131 x 30.8 mu m(2). A PLL with the proposed VCO is also implemented and the rms cycle-to-cycle jitter is 4.34ps.