In described examples, an integrated circuit includes a leadframe structure, which includes electrical conductors. A first coil structure is electrically connected to a first pair of the electrical conductors of the leadframe structure. The first coil structure is partially formed on a semiconductor die structure. A second coil structure is electrically connected to a second pair of the electrical conductors of the leadframe structure. The second coil structure is partially formed on the semiconductor die structure. A molded package structure encloses portions of the leadframe structure. The molded package structure exposes portions of the first and second pairs of the electrical conductors to allow external connection to the first and second coil structures. The molded package structure includes a cavity to magnetically couple portions of the first and second coil structures.