ZC-CFTA-based trans-impedance-mode universal biquad filter with electronic tuning

Abstract

In this topic, a new trans-impedance-mode filter structure realizing low pass (LP), band pass (BP), band reject (BR), high pass (HP) and all pass (AP) filtering functions using three Z- copy current follower trans-conductance amplifiers (ZC-CFTAs) and two grounded capacitors is proposed. The proposed structure realizes all the five standard filtering functions, but one at a time without requiring any inverting type current input signal(s) and component matching conditions. Since ZC-CFTAs are implemented using CMOS topology, thus filter circuit provides temperature insensitive performance parameters. Moreover, the proposed circuit enjoys the features of low active/passive sensitivities, independent electronic tunability of pole frequency and quality factor. The workability of the proposed trans-impedance-mode filter is verified using PSPICE circuit simulation software. © 2014 IEEE.