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Testability of Convergent Tree Circuits
August 1996 (vol. 45 no. 8)
pp. 950-963

Abstract—The testing properties of a class of regular circuits called convergent trees are investigated. Convergent trees include such practical circuits as comparators, multiplexers, and carry-lookahead adders. The conditions for the testability of these tree circuits are derived for a functional fault model. The notion of L-testability is introduced, where the number of tests for a p-level tree is directly proportional to p, rather than exponential in p. Convergent trees that are C-testable (testable with a fixed number of tests, regardless of the tree's size) are also characterized. Two design techniques are also introduced that modify arbitrary tree modules in order to achieve L- and C-testability. Finally, we apply these techniques to the design of a large carry-lookahead adder.

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Index Terms:
Testability, design-for-testability, synthesis-for-testability, C-testability, test generation, regular circuits, iterative logic arrays, tree circuits, functional testing.
R.D. (Shawn) Blanton, John P. Hayes, "Testability of Convergent Tree Circuits," IEEE Transactions on Computers, vol. 45, no. 8, pp. 950-963, Aug. 1996, doi:10.1109/12.536237
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