| 摘要 |
A system and a method for functionally testing fast semiconductor memory chips. The data shifting method proposed here is based on the fact that a low speed tester writes data and data strobe test patterns to a memory block with a low clock frequency. The connection between the tester and the memory chip is subsequently disconnected for all the data and data strobe lines. This can be done by a relay or integrated circuits on an external circuit board or by test modes in the output circuit of the memory chip, that is to say on-chip. The data and data strobe lights are subsequently divided into two groups of the same size and connected to one another. The data and data strobe test pattern written to the first memory block is then shifted with a high clock frequency into a second memory block, from where it is then shifted back into the first memory block in a further read-write cycle with the high clock frequency. The data pattern can subsequently be read out with a low clock frequency by the low speed tester and evaluated.
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