A mechanical arrangement for use in implementing a galvanically-isolated, low-profile micro-inverter primarily, though not exclusively, intended for use with solar panels. The micro-inverter contains a circuitry assembly having a planar transformer formed of two abutting E-shaped core halves, and a chopper device assembly with all chopper devices mounted to a common thermally-conductive plate. To provide passive cooling, heat conduction paths are established, via separate compressive thermally-conductive pads, from a top surface of a top core half of the transformer and from a bottom surface of the conductive plate to large-area portions of opposing internal surfaces of top and base portions, respectively, of an enclosure. The enclosure portions, once secured together to house the circuitry and chopper device assemblies, exert a physical force through the compressive pads to effectively clamp the core halves together and eliminate air gaps that might otherwise form between abutting portions of the core halves.