| 摘要 |
Column decoding is performed using multiply decoded subsets of column address bits bussed across the array to multiple first stage and second stage column multiplexers. That is, for example, in an 8k by 9 memory wherein each subarray contains 16 selectable columns at each bit position, two of the address bits would be fully decoded to provide four buss lines across the chip. Each column has a primary sense amplifier, controlled by one of these four decoded lines. The outputs of each set of four primary sense amplifiers are multiplexed into a secondary sense amplifier, (preferably on a local three-scale buss) and the output of each secondary sense amplifier is selected or deselected by four buss lines which are the decoded signals corresponding to the other two address bits which select one of 16 columns. Preferably multiplexing of the output of the secondary sense amplifiers is accomplished by a three-state buffer, so that the output of these buffers can be accomplished as a wired-or function.
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