CMOS floating active inductor and its applications to bandpass filter and oscillator designs

A CMOS fully differential floating active inductor is realised by exploiting the intrinsic capacitance of the transistor. This technique allows the simulated inductor to operate closer to the f_T, of the technology. Simulation results using SpectreRF with AMS 0.8 μm CMOS process show a self resonant frequency over 1 GHz, and independent tuning of the inductance and the series resistance values. The floating active inductor has been employed in the design of a fourth-order 100 MHz IF bandpass filter and a second-order RF tunable oscillator to demonstrate its performance