Electronically tunable MOSFET-C voltage-mode all-pass filter based on universal voltage conveyor

In this paper, a new voltage-mode first-order all-pass filter with high-input and low-output impedances is presented. The circuit is composed of single universal voltage conveyor (UVC), single capacitor, and an n-channel MOSFET-based voltage-controlled resistor (VCR) that allows to control the pole frequency ω₀ of the filter electronically. No component-matching constraints are required and it has low sensitivity. The proposed filter provides both of inverting and non-inverting outputs at the same configuration simultaneously. The non-idealities of the proposed circuit are also analyzed. The theoretical results are verified by SPICE simulations using TSMC 0.35 μm CMOS process parameters.