An apparatus for the conversion of a digital input signal into an analog output signal, the apparatus including a first circuit receiving the digital input signal that is representative of the analog output signal and suitable for producing a first signal on an output line, and a second circuit for supplying a second signal on the output line, in response to a further digital signal. The further digital signal is a function of external variables, and the union of the first and second signal on the output line forms the analog output signal.