Easily path delay fault testable non-restoring cellular array dividers

Testing of N/spl times/N Non-Restoring Cellular Array Dividers (NRCAD) with respect to path delay faults, is studied in this paper. Design modifications are proposed and a path selection method is suggested. We prove that the selected paths are Single Path Propagating Hazard Free Robustly Testable (SPP-HFRT) and that by measuring their delays the delay along any other path of the divider can be easily calculated. The number of selected paths is impressively small compared to all paths of the divider. The delay overhead of the modified design for all values of N is negligible, while the hardware overhead is small too. This is the first easily testable, with respect to path delay faults, NRCAD design in the open literature.