Digital microelectronic circuit package using buffer dies and programmable device or memory dies

A digital microelectronic replacement package includes at least one buffer die in combination with a programmable device or memory. The buffer die performs the functions of impedance-matching, delay-matching, and voltage-matching, while the programmable device or memory can be used to emulate the logic and/or storage functions of the original digital microelectronic circuit; the package of the invention can be used as a direct replacement for a digital microelectronic circuit without the requirement that the original circuit board be redesigned to accommodate modern voltage, impedance, and delay specifications associated with the programmable device or memory.