Integrated System Labratory

                    Mohsen Zardadi, Mohammad Danaie, and Sasan Naseh

Oscillators are one of the important building blocks in the RF and communication circuits and systems. Due to its low phase noise and ease of implementation, the cross-coupled LC tank CMOS oscillators have received extensive attention in recent years. The amplitude, power consumption and phase noise are among the important performance criteria for oscillators. So far, there have been many research works reported about the phase noise in oscillators. To calculate the oscillation amplitude, methods have been proposed which are mostly based on approximating the waveform of the current entering the LC tank with a square shape or based on the I-V characteristics of the simple model of the MOSFETs.

In this project it is shown that to acquire a higher accuracy, it is better not to attribute any particular shape to the current entering the LC tank. We present a method, by introducing two parameters as function of oscillation amplitude, it is possible to design an oscillator for certain amplitude or power consumption.

Based on this research, one paper “A Method for Designing Complementary Negative Resistance CMOS Oscillators” has been submitted to ISCAS’06. Another paper has been submitted to ICEE’06 as well.

In this project, a CAD tool is to be developed for transistor sizing of Complementary Negative Resistance CMOS Oscillators. Using this CAD tool, the dimensions of the transistors in a cross-coupled LC oscillator can be determined for a given value of tank dissipation, supply voltage and the desired oscillation amplitude.