Abstract: An amplifier circuit having a programmable configuration which is selectable by a user. The amplifier circuit includes a pair of two-input differential input circuits. Each two-input differential input circuit has first and second input terminals, wherein the first input terminal of the first two-input differential circuit is connected to a first circuit input and the first input terminal of the second two-input differential circuit is connected to a second circuit input. The amplifier also includes programmable circuitry for selectively connecting the second input terminals of the first and second two-input differential circuits to either second or third circuit inputs, respectively, or to the fourth and first input terminals, respectively.