Current Feedback Operational Amplifier-Based Biquadratic Filter

Abstract

This paper presents a current feedback operational amplifier (CFOA) based on the topology of the second-generation positive current conveyor (CCII+) and an output buffer. The CCII+ is comprised of n-input and p-input balanced current mirror load OTAs with negative feedback from X node to inverting inputs of the differential pairs. Non-inverting inputs of differential pair make Y input node. The dual-input pair with balanced load structure ensures well-matched circuit characteristic and very low-output offset. This CFOA is biased in the strong inversion region using a dual power supply of ±0.6 V with a bias current of 10 µA. It dissipates the total power of 377 µW and satisfies good CFOA characteristics up to 70 MHz frequency. The CFOA cells have been utilized to design a single input multi output (SIMO) function voltage-mode universal filter which dissipates the total power of 1.79 mW. These circuits have been simulated using cadence simulator tool in 180 nm standard n-tub bulk-CMOS process in its UMC environment.