Hierarchical symbolic analysts of large analog circuits with determinant decision diagrams

A new hierarchical approach is proposed for symbolic analysis of large analog circuits. The key idea is to use a graph-based representation, called determinant decision diagram (DDD). To represent the symbolic determinant and cofactors of the MNA matrix for each subcircuit block. By exploiting the inherent sharing and sparsity of symbolic expressions, DDD is capable of representing a huge number of symbolic product terms in a canonical and highly-compact manner. Further, it enables cofactoring and sensitivity computation to be performed with linear time in the size of DDD. Experimental results have demonstrated that our method outperforms the best-known hierarchical symbolic analyzer SCAPP and even numerical simulator SPICE for small-signal AC analysis.