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Course contents

  • How to Use This Course
  • Reading Path
  • STA Glossary
  • STA Metrics Reference
  • STA Mastery Cheatsheet
  • Timing Paths and Checks16
  • Constraints & SDC Fundamentals20
  • Delay Graph & Path Analysis16
  • Beyond Setup and Hold16
  • Multi-Corner Multi-Mode Signoff16
  • OCV, AOCV, POCV and Variation16
  • Crosstalk and Noise16
  • ECO and Closure16
    • Setup and Hold Closure Order
    • Physical vs Logical ECOs
    • Useful Skew Trade-offs
    • ECO Regression Matrix
      • What to Rerun
      • Regression Matrix Design
      • Avoiding Fix Breaks Fix
      • Closure Dashboards
  • STA Debug Playbook16
  • STA Interview Prep26
  • Capstone Timing Signoff Lab4
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‹ECO and Closure
  1. Topics
  2. Static Timing Analysis
  3. ECO and Closure
  4. ECO Regression Matrix

Part 8 · ECO and Closure · All levels

ECO Regression Matrix

What to rerun after each kind of change, how to design a fast and a full loop, how to stop one fix from breaking another, and what a closure dashboard should show.

  • 4topics
  • 4lessons

An ECO that is not verified is a guess. A regression matrix says, for each kind of change, which checks and which scenarios must be rerun, and splits the work into a quick loop that runs after every batch and a full loop that runs on a schedule. This topic builds the matrix, shows how to batch conflicting ECOs, and ends with the dashboard that tells you whether closure is converging.

Lesson

After it you can...

What to Rerun

Compute the checks a batch of changes needs.

Regression Matrix Design

Pick a fast scenario set and measure its coverage.

Avoiding Fix Breaks Fix

Batch ECOs so conflicting ones are not applied together.

Closure Dashboards

Detect a stall and estimate its floor.

Check yourself Why have both a fast loop and a full loop?

The fast loop gives quick feedback on the scenarios that own most endpoints; the full loop catches the remaining ones before they surprise signoff.

Interview

Be ready to say what you rerun after a hold ECO and why.

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See also

  • Setup and Hold Closure Order
  • Physical vs Logical ECOs
  • Useful Skew Trade-offs