By utilizing a differential tunable active inductor for the LC-tank, a wide tuning-range CMOS voltage-controlled oscillator (VCO) is presented. In the proposed circuit topology, the coarse frequency tuning is achieved by the tunable active inductor, while the fine tuning is controlled by the varactor. Using a 0.18-mum CMOS process, a prototype VCO is implemented for demonstration. The fabricated circuit provides an output frequency from 500 MHz to 3.0 GHz, resulting in a tuning range of 143% at radio frequencies. The measured phase noise is from -101 to -118 dBc/Hz at a 1-MHz offset within the entire frequency range. Due to the absence of the spiral inductors, the fully integrated VCO occupies an active area of 150times300 mum2

A Wide Tuning-Range CMOS VCO With a Differential Tunable Active Inductor

We present a two-stage digitally controlled ring oscillator designed mainly for impulse-radio ultra-wideband (UWB) applications. Each basic stage utilizes a local positive feedback, allowing to achieve steady oscillation at low current consumption levels, and to extend the frequency tuning over an ultra-wide range. The frequency tuning is achieved via the control of the tail resistor in each stage. The circuit is fabricated in a 0.13-mum CMOS technology. It features full UWB coverage at slightly higher than 1.3-V supply voltage, -121.7-dBc/Hz phase noise at a 5.6-GHz carrier, and 10-MHz offset, and less than 5-mW power consumption for the digitally controlled oscillator core alone at 10.18-GHz maximum frequency under 1.3-V supply voltage.

A Two-Stage Ring Oscillator in 0.13- $\mu{\hbox{m}}$ CMOS for UWB Impulse Radio

A dual-operation-mode ring oscillator that employs dual-delay paths is presented. The two operation modes, referred to as the differential and common modes, have different output waveform characteristics and oscillation frequencies. A nonlinear model for the dual-delay-path ring oscillator and the analysis of the stability of each operation mode are proposed to confirm both simulation and measurement results. Furthermore, a method for operation-mode selection is presented. The differential four-stage dual-delay-path ring oscillator is fabricated in a 0.18-μm CMOS technology. Measurements show that the tuning ranges are from 1.77 to 1.92 GHz and from 1.01 to 1.055 GHz for differential- and common-mode operations, respectively.

The Design and Analysis of Dual-Delay-Path Ring Oscillators

A 1-9 GHz linear-wide-tuning-range quadrature ring oscillator has been designed and fabricated in UMC 0.13 ?m CMOS process. The chip was wire-bonded on printed circuit board and tested, showing a liner tuning range from 1 GHz to 9 GHz. Comparative study with other differential ring oscillators demonstrates the advantages of this design in low power consumption and linear-tuning. The oscillator was designed as the voltage controlled oscillator (VCO) for a non-contact vital sign radar sensor. It can also be used for other applications such as ultra-wideband (UWB) impulse radio and clock recovery in broadband optical communications.

A 1–9 GHz Linear-Wide-Tuning-Range Quadrature Ring Oscillator in 130 nm CMOS for Non-Contact Vital Sign Radar Application

This brief presents a low-voltage and low-noise ring voltage-controlled oscillator (VCO) where the phase noise performance is improved by reducing the total channel thermal noise injected into the output node of the VCO during the transition period of the output voltage swing. Implemented in a 65-nm CMOS technology, the proposed ring VCO operates from 485.7 to 1011.6 MHz. At 645 MHz, the measured phase noise is $-$ 110.8 dBc/Hz at an offset of 1 MHz while dissipating 10 mW from a 1-V supply.

A Low-Noise Four-Stage Voltage-Controlled Ring Oscillator in Deep-Submicrometer CMOS Technology

A 5.9-GHz Voltage-Controlled Ring Oscillator in 0.18- m CMOS

This paper presents the design of a 14GHz ring VCO with in-phase/quadrature (I/Q) outputs in a standard 0.18μm CMOS process. A four stage multiple-pass ring oscillator is coupled with frequency doublers for obtaining high frequencies. The VCO core uses delay stages with cross-coupled FETs to increase the switching speed and to improve the noise parameters. The proposed design has a tuning range of 8.5 to 14GHz (49%), and exhibits -95.35dBc/Hz phase noise (@ 1MHz) at a center frequency of 12.7GHz while consuming 146mW from a 1.8V power supply. The results suggest that it is not always necessary to resort to integrated LC networks for 10+ GHz VCO/CCO modules but that cost and area effective ring designs may suffice.

John P. Uyemura

Papers

A 5.9-GHz Voltage-Controlled Ring Oscillator in 0.18- m CMOS

The design of a 14GHz I/O ring oscillator in 0.18μM CMOS