Critical Path Selection for Delay Test Considering Coupling Noise

Identifying the set of real critical paths of a circuit is an important step in delay testing. Since path delays are vector dependent, the set of critical paths selected depends on the vectors assumed when estimating the path delays. To find the real critical paths, it is important to consider the effect of dynamic (vector dependent) delay effects such as coupling noise, supply noise etc. during path selection. In this work a methodology to incorporate the effect of coupling noise during path selection is described. For any given path, both logic and timing constraints are extracted and a constrained optimization problem is formulated to estimate the maximum path delay in the presence of coupling noise.