Pulse tube cryocooler for IR applications

A method of enhancing the passive thermal management of electronic packages, and an electronic package consisting of a vertically-oriented substrate, such as a printed circuit board or the like, a heat-generating electronic module, for example, containing at least one chip which is positioned on a substrate, and a cover plate located adjacent to the module at a predetermined spaced relationship therefrom. The cover plate includes at least one opening located adjacent the module at a predetermined location relative thereto so as to ensure a maximum cooling air flow impinging on the module, and which air flow thereafter passes upwardly between the substrate and the cover plate. The cover plate may be equipped with a heat-sink structure, such as fins, for cooling the module, which structure is adapted to project through the opening formed in the cover plate or to lie flush therewith.