Performance characteristics of an ultra-low power VCO

A CMOS voltage controlled oscillator (VCO) with ultra-low power capabilities is described. A discussion of the VCO's performance characteristics and modeling in terms of simple physics-based expressions is presented. The oscillators have been designed in a commercial 0.18 /spl mu/m CMOS technology and the transistors in the VCOs operate from weak to strong inversion modes at supply voltages from 80 mV to 1.8 V. A new and important feature of …