A programmable gain amplifier (“PGA”) may include a differential amplifier, a pair of input capacitors, a pair of feedback capacitors provided in feedback configuration about the amplifier, a first chop circuit, provided at an input of the PGA and an output of the PGA and a second chop circuit provided at an output of the PGA. The PGA also may include circuit systems to sample voltages across the input capacitors in a sampling phase. The sampled voltages may correspond to a difference between a common mode voltage of input signals to the PGA and a common mode voltage of the differential amplifier. The sampled voltage, thus, defines a common mode voltage at the amplifier's inputs during other phases of operation, when the chop circuits are operational.