Closed-loop,Nonlinearity Analysis and Design of Dual Tuning,Different Control,High FOM Two Stage Ring Oscillator

摘要

A two-stage voltage-controlled ring oscillator is designed. Based on closed-loop system and nonlinearity analysis,oscillation start-up and oscillation frequency is predicted by poles and zeros position in s-plane. With the help of this theory analysis,a high FOM,dual tuning,differential controlled VCO is designed. Jazz 0.18 urn CMOS technology is implemented and the layout area is 47 μm×80 μm including buffers. Current consumption is 5.1 mA under a supply voltage of 1.8 V. Post simulation results show that the coarse tuning range covers 1.894GHz with center frequency 4.5 GHz while the gain is only 66 MHz/V. The phase noise is -96.31 dBc/Hz at 1MHz offset. The FOM value is 166.28 at 1MHz offset.