An example laterally diffused metal oxide semiconducting (LDMOS) device includes a semiconductor substrate of a first conductivity type, active MOS regions, and a lightly-doped isolation layer (LDIL) of a second conductivity type. The active MOS regions include source and drain regions and a plurality of PN junctions. The LDIL is formed above and laterally along the semiconductor substrate, and located between the semiconductor substrate and at least a part of the active MOS regions. The LDIL is doped with dopant of the second conductivity type to cause, in response to selected voltages applied to the LDMOS device, the plurality of PN junctions to deplete each other and to support a voltage drop between the source and drain regions along the LDIL.