Active Inductor Design using Distortion Reduction Technique

Takahide Sato University of Yamanashi

Interdisciplinary Graduate School of

Medicine and Engineering

Toshihiro Ito University of Yamanashi

Interdisciplinary Graduate School of

Medicine and Engineering

Abstract:

This paper proposes a distortion reduction technique for active inductors. Bias current of a MOSFET, which acts as transconductor, is controlled to reduce a distortion of a active inductor. When a input voltage swing of the MOSFET increases, its bias currents is decreased by a control circuit. As a result of this control, transconductance of the MOSFET remains constant. An active inductor using this technique is free from distortion caused by transconductance of a MOSFET. The proposed technique is applied to two basic conventional active inductors and novel low distortion active inductors are derived. HSPICE simulations show that distortion of the proposed active inductor is very low. One of the proposed low distortion active inductors is applied to a 2nd order bandpass filter. Thanks to the proposed technique, the total harmonic distortion of the bandpass filter becomes 0.26% at 1 GHz.