A two-input amplifier is disclosed. The amplifier can include an amplification path for a first input signal that can have adjustable flatness or high-frequency peaking, and an amplification path for a second input that can be substantially independent of the frequency-shaping aspect of the first-input path. The first-input amplification path can include an operational amplifier as an active device and a plurality of passive elements for frequency shaping. The second-input amplification path can include a device that injects its output current into a node of the first path. The signals of the two paths can be combined and appear substantially independently of each other at the output of the amplifier.