An operational amplifier having a first amplification stage with an input terminal to receive a signal to be amplified, and a first output terminal, and a second amplification stage having a first input terminal connected to the first output terminal, and an output terminal to provide the amplified signal. The first and second amplification stages define, between the input terminal and the output terminal, a signal transfer function having first and second poles. The amplifier further includes a decoupling stage having a further input terminal connected to the first stage input terminal, and a further output terminal connected to the second stage output terminal. The decoupling stage is so arranged as to introduce at least one zero in the operational amplifier transfer function.