The main aim of this paper is to present a solution of the triple-input single-output (TISO) filter with mutually independent adjustable pole frequency and with quality factor. The filter is universal, electronically adjustable; it operates in the current mode and includes only two active elements – the so-called voltage differencing transconductance amplifiers (VDTA), – each of them with two controllable transconductances (gm). The implementation of a VDTA element in the 0.18 μm CMOS technology is also included and this model is used in detailed simulation of the proposed active element and also of the proposed universal filter.

Keywords: Current mode, Triple-input single-output (TISO) filter, Universal filter, Voltage differencing transconductance amplifiers (VDTA)