| 摘要 |
PROBLEM TO BE SOLVED: To enable to screen effectively bit lines having leak by pre-charging and equalizing a pair of bit lines once at the time of a test mode, and making a bit line pre-charge/equalizing circuit an off-state after delay of a fixed period. SOLUTION: When a test mode entry signal ϕ EQLOFF is a high level, all equalizing/pre-charge circuits 180 are made an off-state, a delay timer circuit input ϕ delay is made a high level by making a chip internal activating signal/ ACTIVE a low level from a high level, and a timer output signal ϕ EQLOFFB is made a low level after a fixed period t1. Thereby, equalizing operation of a non-selection side is started. But, the equalizing/precharge circuit of a bit line of a selection side is not activated. A period t1 suppresses equalizing operation before read-out of a selected bit line so that a selected bit line is not equalized. |
