Voltage-controlled oscillator

About: Voltage-controlled oscillator is a research topic. Over the lifetime, 23896 publications have been published within this topic receiving 231875 citations. The topic is also known as: VCO.

Highly linear VCO for use in VCO-ADCs

Abstract: A very simple ring-oscillator voltage-controlled oscillator (VCO) structure for use in VCO-ADC applications is presented. It has a greatly improved linearity compared with previously published VCOs. Measurement results of a 1 V, 65 nm CMOS prototype confirm the effectiveness of the proposed approach.

Method and apparatus for fully integrating a voltage controlled oscillator on an integrated circuit

Abstract: A method and apparatus for fully integrating a Voltage Controlled Oscillator (VCO) on an integrated circuit. The VCO is implemented using a differential-mode circuit design. The differential-mode implementation of the VCO preferably comprises a differential mode LC-resonator circuit, a digital capacitor, a differential pair amplifier, and a current source. The LC-resonator circuit includes at least one tuning varactor and two high Q inductors. The tuning varactor preferably has a wide tuning capacitance range. The tuning varactor is only used to 'fine-tune' the center output frequency fo of the VCO. The center output frequency fo is coarsely tuned by the digital capacitor. The VCO high Q inductors comprise high gain, high self-resonance, and low loss IC inductors. The IC VCO is fabricated on a high resistivity substrate material using a trench isolated guard ring. The guard ring isolates the fully integrated VCO, and each of its component parts, from RF signals that may be introduced into the IC substrate by other devices. By virtue of the improved performance characteristics provided by the digital capacitor, the analog tuning varactor, the high Q inductor, and the trench isolated guard ring techniques, the inventive VCO is fully integrated despite process variations in IC fabrication.

A Low-Phase-Noise Multi-Phase Oscillator Based on Left-Handed LC-Ring

Abstract: This paper presents a distributed multi-phase oscillator based on left-handed LC-ring. In contrast to traditional designs that couple multiple LC-tanks through MOSFETs, it uses an LC-ring as a single high-order resonator that generates multi-phase resonant signal. By avoiding coupling MOSFETs which deteriorate phase noise significantly, it can synthesize multiple phases while maintaining the same phase-noise figure-of-merit (FoM) as a single-stage LC oscillator. This also provides a systematic way of trading power for phase noise. The dynamics and the phase noise of the LC-ring oscillator are analyzed based on a mode-decomposition model. We also address the duality of left-/right-handed resonator in the context of oscillator in detail. These analysis was verified by prototypes in a 0.13 μm CMOS process with 0.5 V supply voltage: a four-stage LC-ring oscillator at 5.12 GHz draws 8 mA current and achieves a phase noise of -121.6 dBc/Hz@600 kHz, while a single-stage one at 5.34 GHz draws 2 mA and achieves -116.1 dBc/Hz@600 kHz. There is a good agreement among analysis, simulation, and measurement.

Single-resistance-controlled/voltage-controlled oscillator using current conveyors and grounded capacitors

Abstract: A new single-resistance-controlled/voltage-controlled sinusoidal oscillator using two current conveyors (CCs), two grounded capacitors and three grounded resistors is presented. This oscillator provides the following advantages: (i) independently controllable oscillation frequency and condition by grounded resistors, (ii) easy conversion into a voltage-controlled oscillator, (iii) all the passive components which are suitable for IC implementation are grounded, (iv) very good frequency stability. Experimental results that confirm the theoretical analysis are obtained.

2-GHz RF front-end circuits in CMOS/SIMOX operating at an extremely low voltage of 0.5 V

Abstract: 2-GHz RF front-end circuits [low noise amplifier (LNA), mixer, and voltage-controlled oscillator (VCO)] enabling 0.5-V operation are presented. The circuits were fabricated by 0.2-/spl mu/m fully depleted CMOS/SIMOX technology. The mixer has an LC-tuned folded structure to avoid stacking transistors. Undoped-channel MOSFETs are used in the VCO core and in a complementary source follower as output buffers for the mixer and the VCO. The noise figures of 3.5 dB (LNA) and 16.1 dB (mixer), IIP3 of -6-dBm (mixer), and phase noise of -110 dBc/Hz at 1-MHz offset (VCO) are achieved at a supply voltage of 1 V. They dissipate 2 mW (LNA), 4 mW (mixer), and 3 mW (VCO) at 0.5.