Modified CMOS boot-strapped inductor

摘要

The boot-strapped inductor technique has been shown to be a very effective solution to obtain high Q integrated inductors in bipolar technologies. In this paper, starting from a detailed analysis of this technique when applied to a CMOS technology, we propose a new topology that simplifies the design of active inductors even at frequencies quite close to the transition frequency of the active device. As an example, the design and the performances of an active inductor circuit based on a 0.35 μm CMOS technology is also discussed. The device operates at 2.4 GHz of central frequency, presents at its terminals an equivalent inductance of 6 nH and a Q value as high as 400 at the central frequency, with a bias current of less than 1 mA for a voltage supply of 3.3 V.