A simple CMOS VCO

A novel CMOS VCO is investigated with a design of ring oscillator, where the frequency of the oscillator can be adjusted by the voltage of the substrate. A ring oscillator with five inverters is simulated with Cadence; with 1.6 /spl mu/m technology the range of the oscillation frequency is 271-289 MHz. If implemented with state-of-art technology, the oscillation frequency can be beyond 10 GHz.