Digitally Tunable Voltage-Mode Universal Bi-quad Filter Utilizing a Novel Class AB DDCC

The main motivations and objectives of this paper are to optimally tune central frequency, minimize power consumption and enhance dynamic range by means of a novel class AB differential difference current conveyor (DDCC) structure. The proposed class AB based DDCC structure has the capability to realize four standard filter responses consisting band pass, low pass, high pass and band-reject. Actually, utilization of capacitor banks and digital switch in the proposed circuit on the basis of MOS transistor technology creates the ability to tune pole frequency of the circuit in comparison with conventional capacitors. With respect to obtained results, the maximum power consumption and total harmonic distortion are approximately 570 μW and 4 % for multifunction filter, respectively. Post-layout simulations for class AB based DDCC structure has been carried out in Cadence using TSMC 180nm CMOS process. Additionally, implementing capacitor bank using MOS transistors makes filter appropriate for integrated circuits. Also, filter can be implemented with minimum sensitivity to active and passive elements.