Signature analyzers are very efficient output response compactors for
BIST design. The only limitation of signature analysis is the fault co
verage reduction (aliasing) due to the information loss inherent to an
y data compaction. In this article, in order to increase the effective
ness of ROM BIST, we take advantage from the simplicity of the error p
atterns generated by ROMs and we show that aliasing free signature ana
lysis can be achieved in ROM BIST.