Design and performance analysis of voltage controlled oscillator in CMOS technology

The goal of this proposed work is to design a voltage controlled oscillator (VCO) with good linearity and high gain in 180nm CMOS technology. The circuit is a modification of conventional ring oscillator. The proposed VCO is designed using Current Controlled oscillator and Schmitt trigger. In this paper we propose a new structure by using voltage to current converter, current controlled oscillator and a high speed Schmitt trigger circuit. Simulation results of the proposed VCO show a high linearity which ranges from 68~ 258MHz. This is much higher than Current starved VCO where the linearity ranges from 18.2MHz to 70.5 MHz.