On properties and implementations of inverting ALSC for use in built-in self-testing

Clockwise inverting sequences of original pseudo-random ones are considered effective for two-pattern testing of CMOS circuits. This paper describes a class of circuits which can generate such sequences and conveniently referred as inverting ALSC (autonomous linear sequential circuit). The simulation results show that inverting ALSC generated sequences have strong dependency on the original cyclic structures and can be completely described using some linear recurrence relations. Relationships between original sequences and their inverting ones are illustrated to exhibit correspondence in terms of cycle sets. Then, the possibility of realizing inverting ALSC by simply inserting inverters between stages is discussed. It is further shown that there is no significant difference between two-pattern test capabilities in an original ALSC and the inverting one