An electronic device (100) with one or more semiconductor chips (102) has an inductor (101) assembled on or under the chips. The inductor includes a ferromagnetic body (111) and a wire (104) wrapped around the body to form at least a portion of a loop; the wire ends (104a) are connected to the chips. The assembly is attached to a substrate (103), which may be a leadframe. The device may be encapsulated in molding compound (140) so that the inductor can double as a heat spreader (111c), enhancing the thermal device characteristics.