An integrated circuit includes a transistor, an UTBOX buried insulating layer disposed under it, a ground plane disposed under the layer, a well disposed under the plane, a first trench made at a periphery of the transistor and extending through the layer and into the well, a substrate situated under the well, a p-n diode made on a side of the transistor and comprising first and second zones of opposite doping, the first zone being configured for electrical connection to a first electrode of the transistor, wherein first and second zones are coplanar with the plane, a second trench for separating the first and second zones, the second trench extending through the layer into the plane and until a depth less than an interface between the plane and the well, and a third zone under the second trench forming a junction between the zones.