Design and Simulation of VFA and CFA Based Integrator and Differentiator using NI Multisim and their Comparison

VFA is used for most of the analog circuit design but in many high frequency applications like integrator and differentiator it’s finite slew rate, finite gain bandwidth product limitation degrades its performance. Thus, the introduction of CFA possessing a number of advantages including high slew rate due to its current feedback architecture, closed loop bandwidth that is independent of closed loop gain provides a new dimension to the use of analog circuitry at high frequency. In this paper, we present an analysis and comparison of the maximum frequency range of theinverting integrator and differentiator circuit using both CFA and VFA. We have utilised the pin-to-pin compatibility of CFA with VFA for designing CFA integrator/differentiator. An effort we has been made to design CFA circuits using VFA circuit configuration and at the same time selecting such componentvalues, which gives maximum frequency range for the given circuits maintaining stability. The working capacity and the performance of the proposed circuits examined by simulating the circuits in NI multsim software using 741IC NI model for VFA and AD844 for CFA. These circuits are simulated at large signal, high frequency conditions which challenges their slew rate. Mathematical analysis for CFA topology is done to verify the slight circuit modifications required with CFA circuits. This comparison between older and new technology will be beneficial for the educational institutes in using higher speed op-amps in a simpler way replacing conventional ones.