Advances in Active Inductor Based CMOS Band-Pass Filter

Background: All modern transceiver circuits utilize high-performance band pass filters for proper frequency selection led the researchers to inaugurate the journey of CMOS active inductor. The prime performance requirements of such circuits are very low power dissipation, relatively higher Qfactor with fixed center frequency tuning but a tradeoff among these parameters is inevitable. Method: A number of active inductor-based band pass filters have been designed over the years to obtain better performance trade-offs and a discussion on these designs is presented from their advantages, disadvantages and application point of view. The active inductors are capable of working effectively in band pass filters at very high frequencies up to 11.47 GHz and can be designed to achieve smallest chip area as low as 0.005 mm2. Besides some essential critical parameters such as high-quality factor, narrow bandwidth, central frequency tuning, low voltage operation, very small power consumption etc. are also achievable. Moreover, compared to Gm-C and Q-enhanced LC tank band pass filters, filters with active inductor show better performance in terms of low power consumption, small silicon area, high Q factor and tunability. Conclusion: This review will help the engineers in designing compact and high-performance CMOS band-pass filter circuits for various RF devices.