Tunable Current-Mode First-Order Resistorless Multifunction Filter Using CMOS DX-MOCCII

This article realizes a novel design for a first-order current-mode multifunction filter with many outputs and a single input. One dual-X second-generation multioutput current conveyor (DX-MOCCII) is the one active building block in the proposed filter circuit. A single capacitor and an NMOS transistor working in the linear region are the only externally employed passive components. By acting as a linear resistor, nMOS transistors require a smaller area than traditional resistors and allow the design of tunable current mode filter circuits. The realized current-mode filter provides one high-pass, one all-pass, and two low-pass responses at different outputs. The pole frequency of the first-order filter circuit can be adjusted considerably using an NMOS transistor. The theoretical conclusions are validated using the PSPICE program simulator and the 0.18 µm CMOS process parameters.