An Enhanced Logic BIST Architecture for Online Testing

The objective of using logic BIST for online and periodic testing is to identify defects, like opens, resulting from the wear and tear of the circuit. We have shown that existing test sets have a low coverage for open defects located in scan flip-flops, even though such defects may affect functional operation. Existing Logic BIST structures suffer from the same limitations. A novel Logic BIST architecture to detect such defects is proposed. Unlike other sequences, like checking experiments, the enhancements are simple and independent of the circuit under test.