multi corner multi mode

**Multi-Corner Multi-Mode (MCMM)** — analyzing chip timing across all combinations of operating conditions (corners) and functional modes, ensuring the design works under every real-world scenario. **What Is a Corner?** - A specific combination of Process, Voltage, and Temperature (PVT) - **Process**: SS (slow-slow), TT (typical), FF (fast-fast) — manufacturing variation - **Voltage**: Nominal ± 10% (e.g., 0.75V nominal → check 0.675V and 0.825V) - **Temperature**: -40°C to 125°C (automotive) or 0°C to 100°C (consumer) **Why Multiple Corners?** - Setup (max delay): Check at slow corner (SS, low V, high T) - Hold (min delay): Check at fast corner (FF, high V, low T) - Leakage power: Worst at high T - Each corner can reveal different violations **What Is a Mode?** - A functional operating configuration with different clock frequencies and active blocks - Examples: Full-speed mode, low-power mode, test/scan mode, boot mode - Each mode has different timing constraints **Typical MCMM Analysis** - 5–10 PVT corners × 3–5 operating modes = 15–50 analysis scenarios - Advanced designs: Up to 100+ scenarios - Tool runs STA on all scenarios simultaneously (concurrent MCMM) **Impact** - MCMM is mandatory for signoff — single-corner analysis misses real failures - First silicon success rate correlates strongly with MCMM thoroughness **MCMM** ensures the chip works not just in typical conditions but in every combination of manufacturing variation, voltage, and temperature it will ever encounter.