scan compression

**Scan Compression** is **test-data reduction using on-chip decompression and compaction to cut tester bandwidth and test time** - It is a core technique in advanced digital implementation and test flows. **What Is Scan Compression?** - **Definition**: test-data reduction using on-chip decompression and compaction to cut tester bandwidth and test time. - **Core Mechanism**: Compressed stimuli expand internally into scan patterns while response compactors generate manageable signatures. - **Operational Scope**: It is applied in design-and-verification workflows to improve robustness, signoff confidence, and long-term product quality outcomes. - **Failure Modes**: Uncontrolled X propagation or excessive aliasing can hide defects and weaken diagnostics. **Why Scan Compression Matters** - **Outcome Quality**: Better methods improve decision reliability, efficiency, and measurable impact. - **Risk Management**: Structured controls reduce instability, bias loops, and hidden failure modes. - **Operational Efficiency**: Well-calibrated methods lower rework and accelerate learning cycles. - **Strategic Alignment**: Clear metrics connect technical actions to business and sustainability goals. - **Scalable Deployment**: Robust approaches transfer effectively across domains and operating conditions. **How It Is Used in Practice** - **Method Selection**: Choose approaches by failure risk, verification coverage, and implementation complexity. - **Calibration**: Tune compression ratio with X-masking policy and verify retained coverage against baseline ATPG. - **Validation**: Track corner pass rates, silicon correlation, and objective metrics through recurring controlled evaluations. Scan Compression is **a high-impact method for resilient design-and-verification execution** - It is essential for cost-effective test of modern high-gate-count SoCs.