Scan-chain reordering for minimizing scan-shift power based on non-specified test cubes

Abstract

This paper proposes a scan-cell reordering scheme, named ROBPR, to reduce the signal transitions during test mode while preserving the don't-care bits in the test patterns for a later optimization. Combined with a pattern-filling technique, the proposed scheme utilizes both response correlation and pattern correlation to simultaneously minimize scan-out and scan-in transitions. A series of experiments demonstrate the effectiveness and superiority of the proposed scheme on reducing total scan-shift transitions. The trade-off between our power-driven scan-cell reordering and a routing-driven scan-cell reordering is discussed based on experiments as well.