Impacts of NBTI and PBTI effects on ternary CAM

Ternary content addressable memory (TCAM), which can store 0, 1 and X in its cells, is widely used to store routing tables in network routers. Meanwhile, NBTI (Negative Bias Temperature Instability) and PBTI (Positive Biased Temperature Instability), which increase V_th and degrade transistor switching speed, have become major reliability challenges. In this paper, we propose a novel TCAM architecture to reduce BTI degradation using a bit-flipping technique. This novel TCAM architecture ensures the correctness of read, write and search operations. We also analyze the signal probabilities of TCAM cells, and demonstrate that the bit-flipping technique can balance signal probabilities. By using the bit-flipping technique, 76.40% of the data cells under investigation were found to have signal probabilities close to 50%, which is 62.80% higher than the original architecture. In addition, 92.60% of the mask cells had signal probabilities close to 50%, which is 91.20% higher than the original architecture. When considering the overhead of the bit-flipping technique, the best flipping frequency is once a day.