Design for variability in CMOS logic circuits: Uncommitted motif arrays (UMAs)

Systematic and statistical variability in digital design is becoming increasingly important, and this will be even more pronounced in sub-45 nm technologies. We propose the use of uncommitted arrays of digital sub-blocks, motifs, as the basic building block for CMOS logic. These uncommitted motif arrays maximize functional flexibility, minimize routing complexity, and increase tolerance to systematic variability. The analytical selection of motifs is presented along with a design of a proposed array. We show prototypical design based on the proposed methodology to illustrate the improved regularity of designs, and the resulting routing efficiency compared to traditional uncommitted logic arrays.