Realization of High-Order OTRA-MOSFET-C Active Filters

High-order linear transformation (LT) MOSFET-C active filters with reduced parasitic capacitance effects based on operational transresistance amplifiers (OTRAs) are presented in this paper. A systematic method is developed to realize voltage-mode LT OTRA-based filters efficiently. Based on the proposed design procedures, we can synthesize high-order filters with OTRAs with only MOSFET resistor circuits (MRCs) and virtual grounded capacitors. Signal processing circuits employing OTRAs have almost constant bandwidths because of the use of current-feedback configurations. A third-order Chebychev lowpass filter is demonstrated. HSPICE simulation results that confirm the theoretical analysis are obtained. Furthermore, the proposed circuits can be extended to higher-order filters.