Test Encoding for Extreme Response Compaction

Michael A. Kochte, Stefan Holst, Melanie Elm, Hans-Joachim Wunderlich
2009 2009 14th IEEE European Test Symposium  
Optimizing bandwidth by compression and compaction always has to solve the trade-off between input bandwidth reduction and output bandwidth reduction. Recently it has been shown that splitting scan chains into shorter segments and compacting the shift data outputs into a single parity bit reduces the test response data to one bit per cycle without affecting fault coverage and diagnostic resolution if the compactor's structure is included into the ATPG process. This test data reduction at the
more » ... put side comes with challenges at the input side. The bandwidth requirement grows due to the increased number of chains and due to a drastically decreased amount of don't care values in the test patterns. The paper at hand presents a new iterative approach to test set encoding which optimizes bandwidth on both input and output side while keeping the diagnostic resolution and fault coverage. Experiments with industrial designs demonstrate that test application time, test data volume and diagnostic resolution are improved at the same time and for most designs testing with a bandwidth of three bits per cycle is possible.
doi:10.1109/ets.2009.22 dblp:conf/ets/KochteHEW09 fatcat:7nmqbrvgxzelhflueznzq65jii