A sign switching circuitry is disclosed. In one aspect, the sign switching circuitry includes a first and second differential common-source amplifier having common differential input nodes and common differential output nodes configured such that a differential input signal applied at the common differential input nodes is amplified to a differential output signal at the common differential output nodes with a fixed gain by the first amplifier and by the fixed gain with opposite sign by the second amplifier. The sign switching circuitry also includes a switching circuitry configured to activate the first common-source amplifier and deactivate the second common-source amplifier to amplify the differential input signal by the fixed gain, and to activate the second common-source amplifier and deactivate the first common-source amplifier to amplify the differential input signal by the fixed gain with opposite sign.