The semiconductor integrated device has a conductive region, for example, an external contact pad, configured to be traversed by a current to be measured. A concentrator of magnetic material partially surrounds the conductive region and has an annular shape open at a point defining an air gap area where a sensitive region is arranged, which is electrically conductive and is typically of doped semiconductor material, such as polycrystalline silicon. The device is integrated in a chip formed by a substrate and by an insulating layer, the sensitive region and the concentrator being formed in the insulating layer.