A calibration circuit for calibrating a device to be calibrated includes a variable current generator, a device under test and a control unit. The variable current generator is coupled to a first node of a reference voltage and configured to generate a variable current responsive to variations of the reference voltage. The device under test is a copy of at least one portion of the device to be calibrated, and coupled to the variable current generator to derive, at a second node, a voltage dependent on the variable current. The control unit is coupled to the second node to receive the derived voltage and configured to compare the derived voltage with the reference voltage and to generate, based on a comparison result, at least one calibration signal for adjusting an adjustable electrical parameter of the device under test and the device to be calibrated.