A 8–14 GHz varactorless current controlled LC oscillator in 16nm CMOS technology

This paper presents a new concept of fine frequency tuning in a differential LC oscillator by injecting quadrature phase shifted current into the tank that can replace the use of a conventional varactor, eliminating all limitations associated with it, such as specific bias voltage requirement, limited Q-factor, technology/process uncertainties, model accuracy etc. Wide tuning range of 8-14 GHz is achieved by 5-bit switched capacitor array distributed across the exit legs of the inductor. The circuit is implemented in 16nm CMOS technology. Oscillator core consumes 2.85mW power from 0.9V supply at 10GHz frequency for 400mV single-ended swing. Phase noise is - 108dBc/Hz at 1MHz offset for no tuning current injection.