Dynamic ternary cam for hardware search engine

A five-transistor dynamic ternary content addressable memory (CAM) is presented for high-density data search applications. The data path and the search path are separated to avoid unwanted capacitive coupling at the storage node. To increase the data retention time, the data lines are grounded and dummy search lines are implemented for refresh operations. The proposed CAM cell is fabricated using a 130 nm CMOS process, and occupies an area of 8.99 μm². A prototype array of 64 × 128 search memory has a retention time of 2.84 ms at room temperature with a 1.2 V supply voltage. The hardware search performance is compared with a conventional software-based search scheme, running on two different systems with clock frequencies of more than an order of magnitude faster. The hardware search engine exhibits comparable search speeds while dissipating only 149 mW.