At frequencies around ωx, the inductor can be equivalently modeled by the parallel circuit on the right where the conductance Gp relates to the resistance Rs as The relationship between the maximum oscillation frequency and the process parameter fT for two useful classes of oscillators is developed. Results show that the oscillation frequency of a class of LC-tank oscillators can be substantial...

This paper presents a rigorous phase noise analysis in the 1 f region for the differential CMOS LC-tank oscillator with both nMOS and pMOS switch pairs. A compact, closed-form phase noise equation is obtained, accounting for the noise contributions from both tank losses and transistors currents, which allows a robust comparison between LC oscillators built with either one or two switch pairs. T...

This paper proposes an ultra compact LC-VCO. Due to the speed-up of CMOS digital circuits, jitter of ring oscillators is becoming a critical problem. Even though an LC-VCO has a better phase noise, a layout size of on-chip inductor is a problem as a clock generator. Thus, the proposed LC-VCO consists of a very compact stacked-spiral inductor and active components placed are beneath the inductor...

Log-domain current-mode multiphase sinusoidal oscillators based on all-pass filters are presented in this paper. The first-order differential equation is used for obtaining inverting and non-inverting all-pass filters. The proposed oscillators are realized by all-pass filters whose natural frequency and stage gain can be electronically tuned by adjusting the bias currents. Each all pass filter ...

A general model for injection-locked LC oscillators (LC-ILOs) is presented that is valid for any tank quality factor and injection strength. Important properties of an ILO such as lock-range, phase shift, bandwidth and response to input jitter are described. An LC-ILO together with a half-rate data sampler is implemented as a forwarded-clock I/O receiver in 45-nm CMOS. A strongly-injected lowLC...

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 ...

A new LC quadrature voltage-controlled oscillator (LCQVCO), made with direct coupling of two CMOS LC-VCOs, is presented. In the proposed circuit two identical cross-connected LC-VCOs are coupled together by directly connecting the bulk of the crossconnected transistors of one VCO to the bulk of the MOS varactors of the other VCO in such a way no extra devices are needed for coupling. Thus, no e...