A differential pair for an input stage includes two identical branches in parallel, each branch including a first MOS transistor and a second MOS transistor arranged in series, wherein the first transistor and the second transistor have a channel of the same type, and wherein each of the first transistor and the second transistor has a gate coupled to the same corresponding input of the differential pair and a circuit configured to apply to each of the first transistors a potential difference between a source and a channel-forming region of the first transistor.