An electronically tunable current-mode first-order allpass filter using a CCCCTA

This paper presents a new current-mode first-order allpass filter employing only one current-controlled current conveyor transconductance amplifier (CCCCTA), one capacitor and one MOS resistor. The pole frequency and the current gain of the filter can be controlled electronically by the bias currents of the CCCCTA. Also, both inverting and non-inverting allpass filters can be achieved into a single circuit. No component-matching condition requirements are needed for realizing allpass filtering function. PSPICE simulations using TSMC 0.25 μm CMOS is performed to examine the proposed filter.