Design of Efficient Built-in Self-Test Technique for Faulty TCAM Arrays

The increasing demand for high-speed pattern matching in modern network devices has propelled the widespread adoption of Ternary Content Addressable Memory (TCAM) technology. However, ensuring the reliability and correctness of TCAMs remains a significant challenge due to the inherent susceptibility of memory cells to various types of faults. Memory Built-in Self-Test (BIST) techniques have emerged as a promising solution to address these challenges by enabling efficient testing of TCAMs without external test equipment. This work presents a comprehensive overview of Memory BIST techniques specifically designed for TCAMs. The primary objective of TCAM-BIST is to detect and diagnose faults in TCAM arrays, such as single-cell stuck-at faults, coupling faults, and data-dependent faults. The TCAM-BIST, including deterministic and LFSR based pseudo-random pattern generators, multiple input signature register with space comparator-based fault detection mechanisms, and built-in self-repair techniques. Moreover, the research will explore the utilization of a multiple input signature register with a space comparator for efficient fault detection in TCAM-BIST. The MISR-based mechanism will be analyzed in terms of its ability to accurately detect and diagnose faults in TCAM arrays, while considering the impact on test time and hardware resources.