| 摘要 |
One row of memory cells per sense amplifier bank on a multiple subarray dynamic random access memory (DRAM) are fired while in a test mode. Multiplexors are provided on local I/O lines to ensure that the local I/O lines are not connected to global I/O lines when multiple rows are fired. This provides protection for I/O circuitry not designed to handle the load of multiple local I/O lines coupled in parallel. The multiplexors are controlled by a multiplexor control signal which is separate from row and column decode signals. During a refresh/hammer test, such rows are fired as many times as possible during a refresh period. Then adjacent rows are tested to determine if they were affected by the firing. During the firing, the multiplexors effectively isolate global I/O lines from local I/O lines. |
