A highly flexible sea-of-gates structure for digital and analog applications

A sea-of-gates structure optimized for digital random logic applications as well as for regular arrays and analog circuits is described. Associated with a dedicated design procedure and a systematic metallization strategy, the structure features a full cell-abutment capability and true channelless routing. After reviewing the advantages and limitations of currently available arrays, the main characteristics of the array architecture are presented, and applications to different circuit families are detailed. Design automation tools suited to the structure and design methodology are reviewed. Design results and performance are presented for several macroblocks and are compared with other semicustom approaches. A set of rules which allows an automatic transformation of the sea-of-gates layout into a topologically equivalent full-custom layout, converting semicustom prototypes to full-performance circuits, is presented.< >