slow-slow (ss) corner

**Slow-Slow (SS) corner** represents **the slowest possible transistor performance** — combining slow process, low voltage, and high temperature to create worst-case delay conditions, the critical corner for setup timing verification. **What Is SS Corner?** - **Definition**: Slow process + low voltage + high temperature. - **Characteristics**: Maximum threshold voltage, minimum mobility, lowest drive current. - **Purpose**: Verify setup timing, worst-case delays, minimum performance. **SS Corner Parameters** **Process**: Slow transistors (high Vth, low mobility). **Voltage**: Minimum supply (e.g., 0.9V for 1.0V nominal). **Temperature**: Maximum (e.g., 125°C or 150°C). **Result**: Slowest possible transistor switching. **Why SS Corner Matters?** - **Setup Time**: Critical paths must meet timing at slowest corner. - **Functionality**: Chip must work even with slowest transistors. - **Yield**: Determines which chips pass timing requirements. - **Guardbanding**: Defines safety margins for manufacturing. **What Gets Verified** **Setup Time**: Ensure data arrives before clock edge. **Critical Paths**: Identify and fix slowest timing paths. **Frequency**: Determine maximum operating frequency. **Functionality**: Verify correct operation at slow corner. **Margins**: Ensure adequate timing slack. **Applications**: Setup timing analysis, frequency binning, yield prediction, timing closure. **Typical Values**: 30-50% slower than typical corner, 10-100× lower leakage than FF. SS corner is **the slowest marathon runner** — if design meets timing here, it will work for all manufactured chips.