| 摘要 |
PROBLEM TO BE SOLVED: To perform efficiently screening of a defective device by accessing more memory cells at once, applying voltage and stress. SOLUTION: When a stress applying mode signal (STS bar) is an H state, a device is made a normal operation mode, when it is an L state, the device is made a stress applying mode. In the stress applying mode, in a word line driver WDA, an output driving a word line is made a high impedance state. A stress applying mode boosting circuit TVU drives all word lines in the stress applying mode via N channel MOS transistors TW0-TW3 operating as diodes of a stress applying mode selecting switch circuit TSEL. Thereby, all memory cells MC are selected, access can be performed, and simultaneous screening of defective devices can be performed. |
