120 nm 1.2 V low-noise VCO with over seven octave tuning range

Inverter based voltage controlled oscillators are a fundamental building block in analogue integrated circuit design and enjoy a more compact size and wider tuning range than their inductor capacitor counterparts. In some applications an ultra-wide tuning range is desired and this can be difficult to achieve when combined with the requirement for good phase noise. Presented is a double feedback dual inverter delay cell that demonstrates significantly wider tuning range than previously reported designs whilst maintaining excellent phase noise performance. A key contribution to the work is the fabrication of a 120 nm 1.2 V prototype chip with measured results confirming a tuning range of over seven octaves.