Circuit Arrangement for Memory Search
Original Publication Date: 1987-Jun-01
Included in the Prior Art Database: 2005-Feb-01
A bipolar associative cell has been proposed for semiconductor devices which may be written to and with which one may compare data with the content of the cell. It provides simple circuitry for fast table lookups. (Image Omitted) In a previous design, table lookup is accomplished with a standard random-access memory (RAM) in combination with a large array of compare circuits. This permits the chip to be used as a regular RAM. However, the compare circuits and associated wiring require a large area which, in turn, forces the memory cells to lay in excessively wide pitches. When the chip is used as a directory or DLAT, an extra stage of compare circuit is in the delay path. When the chip is used as a regular RAM, half of the chip area is wasted.