M. Rafei, M. R. Mosavi,
Volume 8, Issue 2 (June 2012)
Abstract
One of the most important features of the Active Inductors (AIs) is their input
equivalent resistance, namely series-loss resistance, which should be low enough to have a
high Quality Factor (QF). Most of the previous methods by this goal did not yield a high
enough QF. This paper presents a new method, namely applying an RC feedback, to cancel
series-loss resistance entirely. As the RC feedback cancels series-loss resistance, it
enhances the Self-Resonant Frequency (SRF) as well. The SRF of the AI has a range as
high as 0.25-12.5 GHz. Compared to the previous reports, the QF has been improved by
applying the RC feedback. The structure is such that the QF can be adjusted independent of
the SRF. For example, a very high quality factor of 13159 at the frequency of 6.6 GHz with
a 2.2 nH inductance is obtained, while noise voltage and power dissipation are less than 4.6
nV Hz and 4 mW, respectively. The AI is designed and simulated using 90 nm CMOS
process and 1.2 V power supply. To the best of authors’ knowledge, this is the first time an
RC feedback has been implemented to cancel series-loss resistance.
