Critical race-free low-power nand match line content addressable memory tagged cache memory

A low-power content addressable memory (CAM)-tagged microprocessor cache using dynamic hierarchical NAND match lines is presented, emphasising the timing impact on overall cache design. Low-capacitive clock loading and lower NAND CAM match line activity factor provide a total cache tag power dissipation savings of up to 64% over a conventional design with NOR match lines. The circuit design, operation and physical layout are described. Results measured on a 0.13-mum low standby power foundry process demonstrate 3.29 fJ/bit/search CAM tag energy at V_DD = 0.9 V and nearly 1 GHz operating frequency at V_DD = 1.75 V. The NAND match lines allow a completely critical race-free cache memory design, which improves robustness at high-scaled process technology nodes, while maintaining fast single-cycle access times.