BeginnerQuestion 40 of 40Source PDF page 34

What is timing signoff?

From PDVerse STA Mentor Guide · pdVerse Mentor Guide

Short Answer

Timing signoff is the formal declaration that a design meets all of its timing requirements under the agreed-upon conditions, and is therefore considered safe to tape out (send off for manufacturing).

Example

Signoff is typically the final stage of the flow, run with tools like PrimeTime or Tempus, using real extracted SPEF parasitics, multiple corners/modes (MMMC), signal integrity effects, and on-chip variation (OCV) all accounted for together.

Why It Matters

Signoff isn't just about a tool printing a zero-violation report; it's about following the agreed methodology properly and having the result be genuinely zero violations, or having any remaining violations explicitly reviewed and waived by the team. It's a rigorous, accountable statement, not simply a clean-looking pass/fail flag.

Mentor Note — Common Mistake

Don't equate 'the tool reported zero violations' with signoff being complete. Real signoff requires that the correct methodology, corners, and constraints were actually used; a zero result from a shortcut or incomplete setup is not a valid signoff.

Visual explanationSTA context: What is timing signoff?
STA context: What is timing signoff?A three-step concept map summarizes the focus, core answer, and practical verification for What is timing signoff?Question focusWhat is timing signoff?Core answerTiming signoff is theformal declaration thata design meets all of…Verify in practiceConfirm the path,constraints, clockassumptions, and timingreport.Understand → explain the mechanism → verify the assumptions

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