Low input impedance trans-impedance type multifunction filter using only active elements

In this paper, a new trans-impedance mode single-input-three-output (SITO) filter using opamp compensation poles is presented. The proposed circuit is composed of two internally compensated operational amplifiers (OAs) and four single-output operational transconductance amplifiers (OTAs), without using any external passive elements. The proposed multifunction filter can realize lowpass, bandpass and highpass responses simultaneously all at low output impedances. No matching condition is required. The circuit is suitable for monolithic implementation either with complementary metal oxide semiconductor (CMOS) or bipolar technologies. All of active sensitivities are low. The performance of the circuit is tested using SPICE simulation program.