diodes of a conventional structure according to another advantage of such an integration with concentric rings the surface of the contact metallizations between diode 23 and thyristor 25 is small with respect to a protection structure comprising only discrete components this limits the parasitic capacitance due to the protection in particular in the present cell a single common contact metallization is provided for the anode of diode 23 and the cathode of thyristor 25 for example in the known implementations due to the parasitic capacitance associated with the protection structure the frequency of the useful signal emitted or received on the pads of the protected circuit cannot be over 10 ghz the tests made by the inventor have shown that the disclosed protection structure can be associated with circuits having pads emitting and or receiving signals at frequencies close to 20 ghz fig5 is a cross section view in the same plane as fig4 a showing an alternative embodiment of a protection cell 51 comprising thyristor 25 and diode 23 of structure 21 described in relation with fig3 protection cell 51 is identical to protection cell 31 described in relation with fig4 a and 4b but for the fact that heavily doped region 41 a of smaller diameter has in top view the shape of a ring with a hollowed central portion and not of a filled ring which decreases the stray capacitance of diode 23.