1.5 V 10-12.5 GHz integrated CMOS oscillators

As both wireless and optical communications systems move towards high-data-rate applications, high-frequency low-phase-noise oscillators are important building blocks in the receiver and transmitter design. CMOS oscillators with integrated inductors are therefore well suited for such applications. This paper describes two integrated CMOS LC oscillators designed for operation over 10 GHz. The first one is based on the ring-coupled quadrature VCO configuration with wide tuning range, while the other is a 4-stage ring oscillator using inductive load. Fabricated in a 0.25-/spl mu/m CMOS technology, both oscillators can operate from a single supply voltage as low as 1.5 V. The highest operating frequencies for the quadrature VCO and ring oscillator are 11 and 12.55 GHz, respectively.