Average placement method with common centroid constraints for analog IC layout design

Adjacent common centroid placement for analog IC layout design

“…placements whose seq-pair is (a 2 b 1 csb 2 a 1 ; b 1 a 1 csa 2 b 2 ) and whose common centroid group is G{ (a 1 , a 2 ), (b 1 , b 2 ), cs}. step1.2: Determine relative coordinates of all cells in G i from S i by the method described in one of the following: [8], [9], IV-B. And regard the cells as a convex super-block.…”

“…The only difference between methods of Ue [8], Fujiyoshi [9], and us is step1.2. Note that this algorithm is similar to the algorithm for 1-D symmetric placement proposed in [13].…”

“…In order to obtain a placement which satisfies common centroid constraint, some methods are proposed [4]- [9]. Strasser et al proposed a method using B*-tree [4], but this method is deterministic.…”

“…Some methods using sequence-pair (seq-pair) [10], which is a topological representation of rectangular block placement, are proposed [6]- [9]. Ma et al proposed a method using Center-based Corner Block List [6], which is an extension of CBL [11].…”

“…The algorithm does not overlap any cells, but the distance between cells in a common centroid group may be redundantly big, and it degrades the immunity. So Fujiyoshi et al improved Ue's method by applying average placement [9]. The only difference with the method of [8] is how to determine relative coordinates of all cells in each common centroid group.…”