Nonidealities of Tow-Thomas biquads Using VOA- and CFOA-based Miller integrators

An analysis and comparison of the performance of Tow-Thomas biquadratic filter sections, implemented with Miller integrators based on current feedback opamps (CFOAs) and voltage opamps (VOAs) was carried out. We found that the implementations with CFOAs show less parameter accuracy and an increased tendency to become unstable. Design criteria to partially overcome these drawbacks and to maximally exploit the inherent high-speed potential of CFOAs were also derived. The theoretical derivations and related results were experimentally validated through implementations from commercially available devices.