A sigma-delta converter including a switching component controlled by a first clock having determined transitions for generating a train of sigma-delta code pulses corresponding to an analog input value. The sigma-delta includes circuits for generating a second clock of a same frequency as the first clock and having a negative transition followed after a defined period of time (d2) by a positive transition. The determined transitions of the first clock controlling the switching element occur during said defined period of time. There is also included a circuit controlled by the sigma-delta code pulse train and said second clock for generating a train of sigma-delta pulses insensitive to the mismatch of the rise and fall times of the switching element thereby improving the linearity and the signal-to-noise ratio of the converter. The control of the period of time allows varying of the energy of the pulses in order to provide pulse trains which, when applied to a sigma-delta decoder, provide an analog output value representative of, but attenuated with respect to, the analog input value.