There has recently been increasing interest in developing highly digital analog-to-digital converter (ADC) structures for on-chip testing and ease of integration in future CMOS processes. An intriguing circuit to utilize in such cases is a ring oscillator voltage-controlled oscillator (VCO), which outputs a clock waveform whose frequency is a function of an input tuning voltage. By comparing th...

A new current-controlled oscillator (CCO) is presented which is suitable for use in low-voltage and lowpower designs. These features, and the low supply dependence of this CCO all stem from using a regenerative mechanism in its primitive delay cells. The circuit is designed and simulated in a 0.8um BiCMOS technology.

VDD A 10 GHz CMOS distributed voltage controlled oscillator (DVCO) is designed in a 0.35pm BiCMOS process technology using only CMOS transistors. The oscillator achieves a tuning range of 12% (9.3 GHz to 10.5 GHz) and a phase noise of -1 14 dBc/Hz at 1 MHz offset from a carrier frequency of 10.2 GHz. The VCO uses two different simultaneous tuning techniques which allow for a coarse and fine I t...

Voltage controlled oscillators are essential building blocks in communication systems and are used as local oscillators to up and down-convert signals in an RF mixer. Despite the continuous improvement in the state of the art of CMOS VCO’s, they still remain the most critical blocks of RF transceivers. The most important parameters of a VCO are phase noise, power consumption and frequency tunin...

A self-correcting quadrature voltage controlled oscillator (QVCO) with phase correcting loop is proposed. It comprises the QVCO core and phase correcting loop, which corrects the quadrature phase error. Two LC VCOs, buffers, and phase shifters are coupled in circular configuration to achieve IQ symmetry. This paper introduces the idea of realizing QVCO with low phase noise and accurate quadratu...

This paper present a single stage CMOS Voltage controlled oscillator with a high oscillation frequency and low power consumption. The VCO is a single stage circuit has a low phase noise due to reduced noise sources. The VCO is intended to operate as a frequency synthesizer in a PLL to generate local oscillator frequency (LO) for an acquisition system, providing in-phase/Q-phase outputs. The per...

This paper presents a new realization of resistorless mixed-mode (i.e. both voltage-mode and currentmode) quadrature sinusoidal oscillator using a new active building block (ABB) called the differential voltage current-controlled conveyor transconductance amplifier (DVCCCTA). The proposed oscillator circuit uses a single DVCCCTA, two grounded capacitors (GCs) and does not employ any external li...

This paper presents the derivations of the voltage transfer functions of the amplifier A, the feedback network β, and the loop gain T of the common-drain (CD) Colpitts oscillator, using the small-signal model of the CD Colpitts oscillator. The derivation of the characteristic equation of the CD Colpitts oscillator is presented. Using the characteristic equation, the equation for the oscillation...

A 2.5 GHz fully integrated voltage controlled oscillator (VCO) for wireless application has been designed in a 0.35μm CMOS technology. A method for compensating the effect of temperature on the carrier oscillation frequency has been presented in this work. We compare also different VCOs topologies in order to select one with low phase noise, low supply sensitivity and large tuning frequency. Go...

This paper presents a general ring oscillator circuit topology for high speed operation, multiphase output and wide range tuning. The topology use sub-feedback inverters to construct fast loop for long chain ring oscillator to achieve high speed. The operating frequency of the ring oscillator is directly proportional to the transconductance (G,) of subfeedback inverters which can be controlled ...