A calibration device (CC) is coupled to a balanced circuit device (MC) comprising first and second outputs respectively provided with first (Z1) and second (Z2) load impedance means. This calibration device (CC) comprises adjusting means (ADM) arranged to adjust said first (Z1) and second (Z2) load impedance means into a load imbalance for linearization purposes, and a coupling means (CM) inserted between the load impedance adjusting means (ADM) and the first and second outputs and arranged to selectively couple the load impedance adjusting means (ADM) to only a chosen one of the first and second outputs, so that the load impedance adjusting means (ADM) is connected in parallel either to the first load impedance means (Z1) or to the second load impedance means (Z2).