12 VLSI Test Principles and Architectures multiple-fault model is more accurate than the single-fault assumption, the number of possible faults becomes impractically large other than for a small number of fault types and fault sites. Fortunately, it has been shown that high fault coverage obtained under the single-fault assumption will result in high fault coverage for the multiple-fault model [Bushnell 2000]; therefore, the single-fault assumption is typically used for test generation and evaluation. Under the single-fault assumption, two or more faults may result in identical faulty behavior for all possible input patterns. These faults are called equivalent faults and can be represented by any single fault from the set of equivalent faults. As a result, the number of single faults to be considered for test generation for a given circuit is usually much less than k × n . This reduction of the entire set of single faults by removing equivalent faults is referred to as fault collapsing
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This note was uploaded on 05/16/2011 for the course ENGINEERIN mp108 taught by Professor Elbarki during the Spring '08 term at Alexandria University.