Content-Addressable Memory capable of a high speed search

DETAILED DESCRIPTION It is, therefore, an object of our invention to improve both the speed of operation as well as the stability of content-addressable memories.
It is a further object of our invention to improve these parameters while confining ourselves to the use of standard, low cost monolithic integrated circuit components.
These and other objects of our invention are achieved by the use of a pair of current switches to sense the contents of a cross-coupled memory cell during the Search mode.
This combination yields the fastest Search time of any content-addressable memory cell known to us but without the drawback of instability.
During the Search mode, only voltage differences are sensed at the internal storage nodes, so that virtually no current is drawn from these nodes.
This minimizes power dissipation within the storage devices but without the drawback of instability.
However, the current level within the current switches is high, thereby ensuring high speed operation.
Match or no-Match situations are detected accurately by large voltage swings on the bit-sense (Search) lines without disturbing the contents of the storage devices, because the storage nodes are isolated from the Search circuitry.
Another useful feature of our invention is that the same circuitry is used both for Writing as well as for Searching.