Design of routing-constrained low power scan chains

Scan-based architectures, though widely used in modem designs, are expensive in power consumption. Recently, we proposed a technique based on clustering and reordering of scan cells that allows to design low power scan chains [1]. The main feature of this technique is that power consumption during scan testing is minimized while constraints on scan routing are satisfied. In this paper, we propose a new version of this technique. The clustering process has been modified to allow a better distribution of scan cells in each cluster and hence lead to more important power reductions. Results are provided at the end of the paper to highlight this point and show that scan design constraints (length of scan connections, congestion problems) are still satisfied.