LC Sine-Wave Oscillators Using General-Purpose Voltage Operational-Amplifiers

Low-Voltage Current Feedback Operational Amplifiers

A number of current feedback operational amplifier topologies suitable for operation in a low-voltage environment are introduced in this paper. Their realization is based on the corresponding low-voltage second generation current conveyor topologies. Important performance factors such as accuracy, bandwidth, and linearity have been considered, and the obtained simulation results have been compa...

A software controlled voltage tuning system using multi-purpose ring oscillators

This paper presents a novel software driven voltage tuning method that utilises multi-purpose Ring Oscillators (ROs) to provide process variation and environment sensitive energy reductions. The proposed technique enables voltage tuning based on the observed frequency of the ROs, taken as a representation of the device speed and used to estimate a safe minimum operating voltage at a given core ...

High-Frequency Low-Noise Voltage-Controlled LC-Tank Oscillators Using a Tunable Inductor Technique

This paper describes 3-GHz and 7-GHz tunableinductance LC-tank voltage-controlled oscillators (VCOs) implemented in 0.18-μm CMOS technology. Unlike the traditional tuning method by a varactor, a tunable inductor is employed in the VCO by using a transformer to compensate for the energy loss. The VCO facilitates the tuning frequency and low noise of the output signals, together with a variable i...

LC-tank CMOS Voltage-Controlled Oscillators using High Quality Inductors Embedded in Advanced Packaging Technologies

Applications of Operational Amplifiers