The dual-X current conveyor (DXCCII): a new active device for tunable continuous-time filters

In this work, a new active device, namely the dual-X current conveyor is proposed for linear tunable continuous-time filtering. The proposed device avails tunability with the aid of triode MOSFETs, while keeping large-signal linearity high. Besides linearity enhancement, the dual-X structure of the active device brings interesting features, which help reduce the required number of active devices and MOSFET resistors in a MOSFET-C continuous-time filter. Also, unlike most MOSFET-C filter structures, there does not exist a matching requirement for the utilized MOSFETs. A CMOS implementation and two application examples (a current-mode Tow-Thomas biquad and a current-mode sinusoidal oscillator) are supplied and simulated to reveal the important advantages.