New 900 MHz CMOS voltage-controlled oscillator for wireless communications

The design of a 900 MHz VCO with a series LC resonance contour implemented in a 0.5 /spl mu/m CMOS technology is presented. From a 3 V supply and with tuning voltage 1.5 V, the amplitude of the output is 1.51 V and a tuning range of approximately 110 MHz is achieved. Proper operation was verified for a supply voltage above 1.2 V. The circuit can be used in various portable communication systems. The results are based on simulations with real technology parameters.