Research And Design On Low-Phase-Noise Low-Power-Consumption Ring VCOs

As the continuous progress of integrated circuit technique,wireless communication technique gains the benefit from it and has a huge development.As the demanding of higher speed and higher data rate,high frequency low-phase-noise low-power VCOs become more and more important as the key block of radio frequency communication circuit.Among these VCOs,ring oscillators have been widely used due to its characteristics of high frequency and low chip area.Compared to LC tank VCOs,ring oscillators consume significantly less chip area with high frequency and large tuning range.However,the phase noise performance of traditional ring oscillators is not as desirable as it's wanted,so the usage of ring oscillators gets limited in some application that demands higher data rate.Achievements and contributions of this work are as follows:1.This work begins with the analysis of basic structure of different types of ring oscillators,and then we give a detailed analysis on the advantages and disadvantages of different types of ring oscillators,and in what application the specific type of oscillator could be used.Besides,in each part of the analysis,this work focus on the interference coupling to the oscillators,and this gives the convenience to solve the phase noise problem for specific type of ring oscillators.2.In order to make the phase noise performance of traditional ring oscillators better,this work focus on the common used cross-coupling technique and analyze the principle of it.And then propose a new type of ring oscillator that utilizing cross-coupling technique.And with the use of frequency multiplication technique,a high frequency signal that the frequency of which is several times of the original one can be get at the output.With the combination of these two technique,ring oscillators can get both high frequency signal and improved phase noise performance.3.This work implements the proposed architecture on cadence spectreRF in TSMC65 nm 1p5m process.The proposed oscillator operates from 4.782 GHz to 7.508 GHz with 44.36% tuning range.The phase noise of the proposed oscillator is-101.3dBc/Hz@1MHz at 4.782 GHz and-97.38dBc/Hz@1MHz at 7.508 GHz respectively.The power consumption is simulated only 32.16 mW and 32.94 mW at 4.782 GHz and 7.508 GHz,respectively.