A method of delay fault test generation

The authors propose an efficient deterministic method of delay fault test generation. For most common circuits, the proposed technique has a time complexity which is polynomial in the size of the circuit, as opposed to existing deterministic methods which, for nearly all circuits, are exponential. They define a type of transition path, the fully transitional path (FTP), and demonstrate that it has several useful properties. An FTP can be created by applying a vector pair derived from a stuck-at test for a primary input. The authors extend this method by using an alternate representation for switching functions, the binary decision diagram, to generate graphs representing stuck-at-tests. The concept of free variables is defined as a tool for deriving several FTPs from one stuck-at test. Preliminary results are presented which indicate that the method provides a higher robust delay fault coverage than pseudorandom patterns at less than one-fifth the cost.<>