The design and implementation of a CMOS LC VCO with 3. 2-6. 1GHz tuning range are presented. This is achieved by enhancing the tuning capability of the binary-weighted band-switching MIM capacitor. The circuit has been implemented in a 0. 18μm RF/Mixed-Signal CMOS process. The measured phase noise is - 101.67dBc/Hz at 1MHz offset from a 5.5GHz carrier,and the VCO core draws 9.69mA current from a 1.8V supply.