Efficient Statistical Analysis of Read Timing Failures in SRAM Circuits

Carnegie Mellon University


A system-level statistical analysis methodology is described that captures the impact of inter- and intra-die process variations for read timing failures in SRAM circuit blocks. Unlike existing approaches that focus on cell-level performance metrics for isolated sub-components or ignore inter-die variability, the system-level performance is accurately predicted for the entire SRAM circuit that would be impractical to statistically analyze via transistor-level Monte Carlo simulations. The accurate bounding of read timing failures using this methodology is validated with silicon measurements from a 64kb SRAM testchip in 90nm CMOS. We further demonstrate the efficacy of this methodology for early-stage design exploration to specify redundancy, required sense amp offset, and other circuit choices as a function of memory size.