A device of protection against electrostatic discharges is formed in a semiconductor substrate of a first conductivity type that is coated with a semiconductor layer of a second conductivity type. A buried region of the second conductivity type is positioned at an interface between the semiconductor substrate and the semiconductor layer. First and second wells of the first conductivity type are formed in the semiconductor layer and a region of the second conductivity type is formed in the second well. A stop channel region of the second conductivity type is provided in the semiconductor layer to laterally separating the first well from the second well, where no contact is present between this stop channel region and either of the first and second wells.