A new topology for transformer based CMOS active inductances

The possibility of realizing the analog block of an RF front end in CMOS technology is quite attractive, since it would lead to the ability of implementing both the digital and the analog sections onto a single chip. The availability of high quality factor (Q) inductors in CMOS technologies is mandatory in order to achieve this goal. This in not an easy task and it is for this reason that several researchers have started to explore the possibility of employing active circuits as part of the inductor itself, in order to compensate for the passive inductor´s losses. In this paper, we propose a new topology for the design of integrated transformer based high quality active inductors. As an example, we have designed an active inductor circuit based on a 0.35 μm CMOS technology and capable of behaving as a pure inductance above 2.4 GHz.