Level-Testability of Multi-operand Adders

Level-testability of multi-operand adders consisting of carry save adders is shown by showing test design for them. A multi-operand adder is a main part of a multiplier. 6L+2 patterns are sufficient to test a multi-operand adder under cell fault model, where L denotes the depth of the multi-operand adder. A test method of the multi-operand adder used as a partial product compressor in a multiplier is also shown. This result gives an upper bound of the number of required test patterns for a multi-operand adder in any multiplier.