A Tunable High-Q Active Inductor with a Feed Forward Noise Reduction Path

The analysis and design of a tunable low noise active inductor is presented. The noise performance of the proposed gyrator-based active inductor is improved without either degrading its quality factor or consuming more power using a linear feed forward path (FFP). The proposed low noise active inductor has been designed and fabricated in a standard 0.18-m CMOS technology. The measurements show a 3 folds improvement in the input noise current compared to that of the conventional active inductors. The active inductor was tuned and measured at the resonance frequency of 2.5 GHz which could be extended to as high as 5.5 GHz with a quality factor of 30. The circuit draws 4.8 mA from a 1.8 V supply.