| 摘要 |
An improved driver permits the driving of a functional array of four-state cells having only two bit lines per cell while providing for the writing of any one of four possible logical states (0, 1, X, Y) into the array during one write cycle. In a preferred form, the improved driver includes a first pair of field effect transistors which are selectively operated during write and search/select cycles to couple a pair of junctions (or nodes) in the driver to the pair of data bit lines of a cell. In the absence of "don't care" signals, additional field effect transistors respond to input data to the driver to apply complementary signals (01 or 10) to the nodes for application to the respective bit lines. In response to the receipt of "don't care" signals, field effect transistors in the driver electrically connect the two nodes causing the same selected signal level (00 or 11) to be applied to the data bit lines. A pair of field effect transistors are selectively operated during read cycles to couple the data bit lines to respective sense amplifiers. In a preferred form, the driver is comprised of complementary field effect transistors operated in the enhancement mode.
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