Abstract
In this project the design of a simple ring oscillator VCO was explored. This new proposed ring oscillator uses inverter delay cells including transmission gates, in order to turn off one transistor in the next delay cell before the other transistor turns on. It is hoped that the use of this sort of "break-before-make" circuitry will reduce jitter compared to a traditional inverter-based ring oscillator. The jitter performance of the new proposed VCO was simulated across PVT corners, and compared to that of a traditional inverter-based ring oscillator. Although the new proposed VCO using transmission gates did achieve slightly better jitter performance, the improvement was not as much as expected. It is hoped that further improvements in jitter performance can be obtained through careful optimization of the device sizes in the new proposed VCO.