Abstract: A chip stack comprising a flex circuit including a flex substrate having a first conductive pattern disposed thereon and a plurality of leads extending therefrom. Also included in the chip stack are at least two integrated circuit chip packages. The integrated circuit chip packages may be electrically connected to the first conductive pattern of the flex circuit such that the integrated circuit chip packages are positioned upon respective ones of opposed top and bottom surfaces of the flex substrate. Alternatively, one of the integrated circuit chip packages may be positioned upon the top surface of the flex substrate and electrically connected to the first conductive pattern, with the remaining integrated circuit chip package being attached in a non-conductive manner to the bottom surface of the flex substrate such that the conductive contacts of such integrated circuit chip package and the leads collectively define a composite footprint for the chip stack.