Current-feedback amplifiers versus voltage operational amplifiers

This paper compares the main performance parameters of the current feedback opamp (CFOA) with those of a conventional voltage opamp (VOA). To make the comparison effective, a folded cascode VOA is considered (which is charact erized by similar features and topology) and the same power consumption was assumed for both amplifiers. The work confirms that the CFOA can provide h igher bandwidth, albeit at the expense of reduced loop gain. Noise performa nce is also analyzed. Input-referred noise generators are determined and so me peculiar CFOA features, having no equivalence in conventional opamps, ha ve been highlighted. It is shown that the CFOA has slightly lower noise vol tage, but a larger noise current. Simulations are given which are in very g ood agreement with expected results.