| 摘要 |
PROBLEM TO BE SOLVED: To variably set timing of a write command read time (tRWL) for a RAS bar signal shorter than a specified value and a precharging time (tRP) to be desirably measured by executing operation tests at the tRWL for a RAS bar signal shorter than a specified value and the tRP. SOLUTION: When a RAS bar is set to 'L' (active), an internal RAS bar of an output end (a) becomes active, and a potential of a word line is raised to 'H'. Thereafter, a WE bar signal is set to 'L', and a write operation is started (timing t1). After the WE bar is input, the RAS bar is reset via a Delay 1 to 'H' (timing t2). Thus, the potential of the word line is lowered to the 'L', and writing in the memory cell is ended. Thereafter, an external RAS bar is set to the 'H', and reset (timing t3). A tRWL observed at an external signal is (t3-t2), but in a substantial operation, the tRWL becomes (t2-t1) according to the internal RAS bar signal.
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