Testing Inter-Word Coupling Faults of Wide I/O DRAMs

Abstract

Wide-I/O dynamic random access memory (wide I/O DRAM) is one of promising solutions to increase the memory bandwidth. Similar to modern double-data-rate DRAMs, the minimum burst length of wide I/O DRAM is at least two. Thus, either a read or a write operation is executed, two words will be read or written at least each time. This causes that the testing of inter-word coupling faults becomes complicated. In this paper, we propose a method to modify conventional March tests into modified March tests which can fully cover inter-word coupling faults of wide I/O DRAMs with minimum burst length of two and programmable burst order. Furthermore, the test complexity of modified March tests for different burst lengths is analyzed. Results show that the test time of modified March tests is the shortest if the longest burst length is set to apply the modified March tests. Results of fault coverage analysis show that the modified March test can provide 100% fault coverage of simple inter-word coupling faults.