Detecting Bridging and Stuck-At Faults at Input and Output Pins of Standard Digital Components

Due to the advances in the integrated circuit technology, there is an increasing importance in testing bridging (short circuit) failures in digital networks. Unfortunately, very little work has been done in this area. This paper presents the schemes for the detection of feedback bridgings between the inputs and outputs through the observation of oscillation and asynchronous behavior of sequential networks created by bridging faults. The lower and upper bounds on the number of tests for detecting all feedback bridging faults are given. Conditions for the undetectability of input bridgings are given and a method for testing input bridgings is presented. The results are generalized to detect bridging and stuck-at faults in the input and output lines of a multiple-output network. Finally, the complete test sets are given for detecting input, output and feedback bridgings as well as stuck-at faults at the input and output pins of the standard integrated circuit chips including shift registers, counters, decoders, multiplexers, adders/subtracters, multipliers, dividers and RAM. Future unsolved problems in this area are also given.