An electronic device includes first leads along a first side, second leads along a second side, first and second dies, and a magnetic assembly with a multilevel lamination structure with first and second windings and a conductive guard trace. The lamination structure includes the first winding in a first level, and the second winding in a different level. The guard trace is between the first patterned conductive feature and the second side of the package structure. A first set of electrical connections couple the first die, the first winding, and one of the first conductive leads in a first circuit, and a second set of electrical connections couple the second die, the second winding, the guard trace and one of the second conductive leads in an isolated second circuit.