Scan Architecture with Data Observation for Multiple Scan Cell Fault Diagnosis

The scan architecture has been widely used to detect faults in digital circuits. Since the scan test utilizing the scan architecture proceeds under the assumption that no faults exist in the scan chain, the scan chain diagnosis must be performed before the scan test. Most scan chain diagnosis methods address only a single scan cell fault within each scan chain. If the multiple scan cell fault diagnosis is possible, it suffers from low diagnostic performance and long diagnosis time. Therefore, scan architecture with data observation for multiple scan cell fault diagnosis is proposed to address these limitations. The experimental results indicate that the proposed scan architecture achieves the multiple scan cell fault diagnosis with maximum diagnostic resolution. In addition, less diagnosis time is required compared to the conventional methods.