A low‐noise current‐reused CMOS active inductor by exploiting G m ‐boosting technique

Abstract

This work introduces a new low-noise current-reused CMOS active inductor (AI) based on Gyrator-C configuration. In the proposed AI, a simple common-source amplifier is utilised for boosting effective Gm and improving noise performance of the AI. While the Gm-boosting technique improves the noise performance as well as the quality factor of the inductor, a resistor is also added to the feedback path for more quality factor improvement. Rigorous analysis of the proposed circuit shows a significant noise performance and quality factor enhancement. In order to verify the concept and confirm the mathematical analysis, the AI is designed and simulated in a commercial 0.18 μm RF-CMOS technology. The simulation results show that the proposed inductor operates in 1 to 7.2 GHz frequency range, has a 9 nH inductance at 2.864 GHz frequency and 650 μW total power dissipation at 1.8-V supply voltage. Maximum quality factor of 90 is achieved at 2.864 GHz frequency and a quality factor greater than 40 is obtained from 2.4 to 3.3 GHz. The input-referred current noise of the proposed inductor is as low as 22 pA / √ Hz showing 30.5% improvement compared to the conventional AI. The proposed AI is also tunable and sweeping the tuning voltage results in changing extracted inductance from 4.35 to 15.2 nH with only a chip area of 0.003 mm2. Post-layout and different Monte Carlo simulation results also confirm the robust operation of the proposed AI against different process non-idealities.