Design and Linearity Analysis of a Dual Control 5-Stage CSR-VCO for RF Applications

This paper presents dual control voltage in the conventional 5 -stage current-starved ring voltage-controlled oscillator (CSR-VCO) to provide a wider tuning range and fine-tuning possibilities for radio frequency (RF) applications. The circuit is implemented in $45 \mathrm{~nm}$ CMOS $1 \mathrm{~V}$ process technology. The proposed circuit is found to have an oscillation frequency range from 6.51GHz to 13.66GHz for the first control voltage $(0.8 \mathrm{~V}-1.8 \mathrm{~V})$. On the other hand, the second control voltage $(1 \mathrm{~V}-1.8 \mathrm{~V}$) demonstrates a better linear frequency range, spanning from 5.65GHz to 13.66GHz when the first control voltage is fixed at $1.8 \mathrm{~V}$. Modifying the first control voltage, in conjunction with the second, results in precise changes in the frequency level, providing the potential for fine-tuning in radio frequency applications. The 1MHz offset phase noise of the VCO at the maximum output frequency of 13.66GHz is found to be $-75.96 \mathrm{dBc} / \mathrm{Hz}$ and the corresponding power consumption is found to be $2.68 \mathrm{~mW}$.