A configuration for the realization of voltage-mode second-order filters employing a single operational transresistance amplifier (OTRA) as the active element is presented. This topology can synthesize lowpass, highpass, bandpass, notch and allpass filtering functions. The presented filters are suitable for MOS-C implementation, yielding the filter parameters to be electronically tunable. Theoretical analysis is verified with PSPICE simulation. (C) 2008 Elsevier GmbH. All rights reserved.