The amplifier includes an input amplifier stage, an output amplifier stage cascode-connected with the input amplifier stage, and a load stage connected to the output stage. The load stage includes a plurality of circuits each including a capacitive component and an inductive component having a Q greater than 10, and having respective different resonant frequencies. All the gain curves respectively associated with all the circuits have, to within a stated tolerance, the same maximum gain value at the resonant frequencies. The gain curves respectively associated with two circuits having respective immediately adjacent resonant frequencies overlap below a threshold 3 dB, to within a stated tolerance, below the maximum gain value.