Using a single input to support multiple scan chains

Abstract

Single scan chain architectures suffer from long test application time, while multiple scan chain architectures require large pin overhead and are not supported by boundary scan. We present a novel method to allow a single input line to support multiple scan chains. By appropriately connecting the inputs of all circuits under test during ATPG process such that the generated test patterns can be broadcast to all scan chains when actual testing is executed, we show that 177 and 280 test patterns are enough to detect all detectable faults in all 10 ISCAS'85 combinational circuits and 10 largest ISCAS'89 sequential circuits, respectively.