Low-cost associative memory

The authors describe the design of two high-density MOS associative memory cells. The first cell is suitable for data management applications, having three internal states including the DON'T CARE (mask) condition. The second cell is suitable for parallel processing applications and has the capability of selected bit writing. Both cells consume about 20 mil/SUP 2/ of silicon area, which allows the implementation of 512 bits on a chip. Varactor bootstrapping is used to enhance the storage node voltage for improved cell operation. The use of a compatible bipolar transistor is discussed.