Versatile voltage-mode active-only biquad with lossless and lossy integrator loop

This paper presents a realization of a voltage-mode active-only biquad using operational amplifiers (OAs) and operational transconductance amplifiers (OTAs). The circuit configuration is obtained from a second-order integrator loop structure with lossless and lossy integrators. The proposed circuit can realize low-pass, band-pass, high-pass, band-stop and all-pass transfer functions by a suitable choice of input and output terminals. The circuit characteristics can be electronically tuned through adjustment of the transconductance gains of the OTAs. An example is given, together with simulated results by PSPICE. The circuit configuration is very suitable for implementation in both bipolar and CMOS technologies.