A semiconductor die including: - a structural body including: a substrate, of P-type doped silicon, having a front side and a back side; and an epitaxial layer, of N-type doped silicon, extending on the front side of the substrate and having an own front side, wherein the back side is coupleable to a base plate of a package, the structural body including a first region and a second region, the second region being a peripheral region of the semiconductor die surrounding, in top plan view, the first region; - a dielectric layer over the front side of the epitaxial layer; - one or more semiconductor power devices arranged and grouped together in the first region at the front side of the epitaxial layer, the one or more semiconductor power devices being coupled to the epitaxial layer by means of a thermally conductive coupling interface (26; 30; 32); a plurality of low-voltage peripheral devices grouped together in said second region; the structural body further comprising a third region extending, in said top plan view, between the first region and the second region, the third region housing trench-insulation means, which extend in the structural body starting from the front side of the epitaxial layer towards the back side of the substrate along a first direction, surrounding and delimiting the first region, wherein the trench-insulation means include a plurality of trenches arranged at a distance from one another along a second direction orthogonal to the first direction, thus delimiting portions of the structural body (2; 3) between one trench and an adjacent trench, wherein the trench-insulation means have an extension (d), along said second direction, given by the sum of the extensions, along the second direction, of each trench of said plurality of trenches plus the extension, along the second direction, of said portions of the structural body extending between one trench and the adjacent trench, wherein the extension (d) is greater than a thickness (h) of the structural body from the front side of the epitaxial layer to the back side of the substrate along the first direction, wherein each trench includes a first filling layer of silicon oxide and a second filling layer of polysilicon, completely contained within the first filling layer, so as to form an obstacle to heat conduction from the first region towards the second region along the second direction. - a structural body including: a substrate, of P-type doped silicon, having a front side and a back side; and an epitaxial layer, of N-type doped silicon, extending on the front side of the substrate and having an own front side, wherein the back side is coupleable to a base plate of a package, the structural body including a first region and a second region, the second region being a peripheral region of the semiconductor die surrounding, in top plan view, the first region; - a dielectric layer over the front side of the epitaxial layer; - one or more semiconductor power devices arranged and grouped together in the first region at the front side of the epitaxial layer, the one or more semiconductor power devices being coupled to the epitaxial layer by means of a thermally conductive coupling interface (26; 30; 32); a plurality of low-voltage peripheral devices grouped together in said second region; the structural body further comprising a third region extending, in said top plan view, between the first region and the second region, the third region housing trench-insulation means, which extend in the structural body starting from the front side of the epitaxial layer towards the back side of the substrate along a first direction, surrounding and delimiting the first region, wherein the trench-insulation means include a plurality of trenches arranged at a distance from one another along a second direction orthogonal to the first direction, thus delimiting portions of the structural body (2; 3) between one trench and an adjacent trench, wherein the trench-insulation means have an extension (d), along said second direction, given by the sum of the extensions, along the second direction, of each trench of said plurality of trenches plus the extension, along the second direction, of said portions of the structural body extending between one trench and the adjacent trench, wherein the extension (d) is greater than a thickness (h) of the structural body from the front side of the epitaxial layer to the back side of the substrate along the first direction, wherein each trench includes a first filling layer of silicon oxide and a second filling layer of polysilicon, completely contained within the first filling layer, so as to form an obstacle to heat conduction from the first region towards the second region along the second direction.