TRAM: a design methodology for high-performance, easily testable, multimegabit RAMs

An architecture is proposed for multimegabit dynamic RAMs (random-access memories) that achieves higher testability and performance than the conventional four-quadrant RAMs. Applying the principle of divide and conquer, the RAM is partitioned into modules, each appearing as the leaf node of a binary interconnect network. Such a network carries the address/data/control bus, permitting the nodes to communicate among themselves as well as with the outside world. This architecture is shown to be easily testable. Parallelism in testing and partial self-test result in a large savings of testing time; the savings is independent of the test algorithm used. Unlike other testability schemes, this approach promises improved performance with only a small increase in chip area. It is also shown that the architecture is easily partionable and restructurable, with potential for yield and reliability improvement