A RESURF LDMOS integrated structure realized in a first region (drain well) of a first type of conductivity defined in a semiconductor substrate of opposite type of conductivity and comprising a source region of said first type of conductivity formed in a body region of said opposite type of conductivity. Said body region is contained within a surface portion (body buffer region) of the first region that is more heavily doped than the rest of the region to avoid punch-through when the structure operates as a high side driver. <IMAGE>
