A study of some reported LC quadrature voltagecontrolled oscillators (LC-QVCO) is performed in which it is shown that robustness of the quadrature oscillation varies depending on the coupling configuration. Next, a new superharmonic LC-QVCO is proposed in which the common source node in either of two identical crossconnected LC-VCOs is coupled via a capacitor to the node common between the two ...

MOS varactors are used extensively as tunable elements in the tank circuits of RF voltage-controlled oscillators (VCOs) based on submicrometer CMOS technologies. MOS varactor topologies include conventional D=S=B connected, inversion-mode (I-MOS), and accumulation-mode (A-MOS) structures. When incorporated into the VCO tank circuit, the large-signal swing of the VCO output oscillation modulates...

In this paper we propose new oscillator architecture (VCO2) and we compare it with a simple oscillator (VCO1). We describe the design and implementation of the differential LC-VCO for wireless applications. In this work we develop an analytical framework for determining the best VCO for a high-frequency synthesizer design based on the constraints of the application. We show methods for reducing...

(VCO) phase-locked loop (PLL) and ring-VCO PLL topologies with low-phase noise. Differential control loops are used for the PLL locking through a symmetrical transformer-resonator or bilaterally controlled varactor pair. A differential compensation mechanism suppresses out-band spurious tones. The prototypes of the proposed PLL are implemented in a CMOS 65-nm or 45-nm process. The measured resu...

This paper describes a low-noise, 900-MHz, voltagecontrolled oscillator (VCO) fabricated in a 0.6m CMOS technology. The VCO consists of four-stage fully differential delay cells performing full switching. It utilizes dual-delay path techniques to achieve high oscillation frequency and obtain a wide tuning range. The VCO operates at 750 MHz to 1.2 GHz, and the tuning range is as large as 50%. Th...

In this paper, we describe an original method for determining the optimal operating point of the active part (transistor) of an LC oscillator leading to the minimum phase noise for given specifications in terms of power consumption, oscillation frequency and for given devices (i.e., transistor and resonator). The key point of the proposed method is based on the use of a proper LC oscillator arc...

This paper presents design, fabrication and characterization of two differential Colpitts voltage controlled oscillator (VCOs) cross-coupled VCO (CC-VCO) and double cross-coupled VCO (DC-VCO) in InGaP/GaAs HBT technology. Their main parameters like the oscillation frequency, output power and phase noise performance are measured and compared with other recently published studies. In the cores of...