A multi-tap inductor based 2.0–4.1 GHz wideband LC-oscillator

Abstract

A voltage controlled LC-oscillator (LC-VCO) has been designed to cover a wide range of frequencies (2.0-4.1 GHz) using an area efficient and switchable multi-tap inductor and a capacitor bank. The multi-tap inductor provides a significant area advantage, and in spite of a degraded Q, provides an acceptable phase noise of -123 dBc/Hz and -113 dBc/Hz at an offset of 1 MHz at carrier frequencies of 2 and 4 GHz respectively. Implemented in a 0.13 μ-m CMOS technology, the oscillator occupies an active area of 0.095 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . With ≈ 69 % tuning range and a maximum K <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">VCO</sub> of about 360 MHz/V, it consumes 9-16 mW of power. It can be used for cognitive radio and other wide-band and multi-band RF applications.