Symmetry constraint based on mismatch analysis for analog layout in SOI technology

The conventional tools for mismatch elimination such as geometric symmetry and common centroid technology can only eliminate systematic mismatch, but can do little to reduce random mismatch and thermal-induced mismatch. As the development of VLSI technology, the random mismatch is becoming more and more serious. And in the context of Silicon on Insulator (SOI), the self-heating effect leads to unbearable thermal-induced mismatch. Therefore, in this paper, we first propose a new model which can estimate the combination effect of both random mismatch and thermal-induced mismatch by mismatch analysis and SPICE simulation. And in order to meet the different sensitivities of different symmetry pairs, an automatic classification tool and a configurable optimization process are also introduced. All of these are embedded in the floorplanning process. The final experimental results prove the effectiveness of our method.