Regularity-oriented analog placement with diffusion sharing and well island generation

This paper presents a novel regularity evaluation of placement structure and MOS analog specific layout techniques called diffusion sharing and well island generation, which are developed based on sequence-pair. The regular structures such as topological row, array and repetitive structure are characterized by the way of forming subsequences of a sequence-pair. A placement objective is formulated balancing the regularity and the area efficiency. Furthermore, diffusion sharing and well island can be also identified looking into forming of a sequence-pair. In experiments, we applied our regularity-oriented placement mixed with the constrait-driven technique to real analog designs, and attained the results comparable to manual designs even when imposing symmetry constraints. Besides, the results also revealed the regularity serves to increase row-structures applicable to the diffusion-sharing for the area and wire-length saving.