Delay testable sequential circuit designs

New method of a sequential circuit design based on using mixed description of the circuit behavior is suggested. A combinational part behavior of a sequential circuit is represented with the composition of ROBDDs (Reduced Ordered Binary Decision Diagrams) and monotonous products. The method provides fully delay testability of a combinational part of a sequential circuit. Algorithms of deriving test pairs for robust PDFs (Path Delay Faults) are suggested. The method is oriented to cut the path lengths of the obtained circuits.