New high-performance voltage-controlled LC-oscillator

A VCO with serial LC-configuration, loaded with low input/output impedances of a resonance loop-amplifier, provides stable frequency of oscillations, and employs very low-Q inductors on silicon. The control voltage changes the bias in one of the amplifying sections, and indirectly the voltage over the p-n junction, which acts as a varactor. This way the separation between the control and oscillation circuits is provided effectively. On 0.8 /spl mu/m BiCMOS technology (17 GHz NPN), the new VCO circuit operates with 0.4 mW from only 1 V, and produces 600 mV sinusoid at 6.6 GHz with 3.6% non-linearities, and low-phase noise, suitable for modern communication and microprocessor circuits.