A configuration for realizing low input and high output impedances current-mode multifunction filters using multiple output second-generation current conveyors (MOCCIIs) is presented. From the proposed circuit configuration, first-order allpass, highpass, lowpass and second-order allpass, notch, bandpass filters can be obtained. The simulation results confirm the theoretical analysis. 1. Introduction Current conveyors (CCs) are receiving much attention for their potential advantages such as inherent wider signal bandwidths, simpler circuitry and larger dynamic range [1, 2]. Current-mode active filters with low input impedance and high output impedance are of great interest because they can be directly connected in cascade to implement higher order filters [3, 4]. Several current-mode first-order allpass filters using various active components have been reported. Some circuits use two second-generation current conveyors (CCIIs) to realize such a first-order allpass filter function with high output impedance [5]. However, the number of passive components they used are not canonical. Some first-order circuits use one active component [6, 7]. However, their input impedances are not low. Some first-order circuits use one active element, one capacitor, and one resistor [8–10]. However, these circuits have not the advantage of low input impedance and the capacitors they used are not grounded. In 2007, Metin et al. [11] propose a current-mode first-order allpass filter using two CCIIs, two grounded resistors and one grounded capacitor with low input and high output impedances. In 2009, Lahiri and Chowdhury [12] proposed a current-mode first-order allpass filter using one current differencing transconductance amplifier (CDTA) and one grounded capacitor with low input and high output impedances. As the function of CDTA can also be replaced by two CCII and one operational transconductance amplifier (OTA) [12], if the structure of [12] is constructed by CCIIs and OTA, it requires two CCIIs and one OTA. In this paper, a new current-mode circuit configuration with low input and high output impedances uses two multiple output second-generation current conveyors (MOCCIIs) is presented. The first-order allpass, highpass, and lowpass filters can be obtained from the proposed circuit configuration. Several current-mode universal biquadratic filters with single-input and multioutput were presented in the literature [13–15]. However, the input impedances of the circuits in [13, 14] are high. Moreover, at least three CCIIs are required in [14, 15]. Several current-mode
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