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CDC / RDC · All levels

CDC Tool Flow: Silicon PPA Impact

Silicon PPA Impact for CDC Tool Flow.

Silicon PPA and reliability impact

Signoff dashboards keep risk visible across milestones.

Area drivers

  • extra synchronizer stages

  • FIFO buffering

  • diagnostic observability logic

Power drivers

  • additional flops

  • always-on reset logic

  • debug monitors

Timing/latency impact

  • added latency through synchronizers

  • pointer synchronization delays

PD consequences

  • placement proximity of sync stages

  • clock/reset tree interactions

Verification burden

  • formal liveness reruns

  • stress simulation matrix

diagram
PPA / RELIABILITY — CDC Tool Flow
area/power/latency vs reliability margin

Key takeaways

  • Reliability has implementation cost

  • Track that cost explicitly in signoff decisions

Design option reliability curve

diagram
METASTABILITY ENVELOPE — CDC Tool Flow

probability of unresolved state
  ^
  |\
  | \
  |  \
  |   \
  +------------------------------> settle time
      short settle      long settle

Design lever: more settle time and correct synchronizer topology increase MTBF.

CDC/RDC deep dive

Signoff is an evidence governance problem across teams.

Concept diagram

diagram
CDC SIGNOFF LOOP

analysis -> triage -> fix/waive -> review gate -> dashboard

Metric graph

diagram
CRITICAL OPEN COUNT

week1 34
week2 22
week3 10
week4 0

Reports and artifacts

  • critical by owner

  • waiver quality

  • review gate status

  • closure trend

Mini case study

Pass rates improved while critical waivers aged out of policy; dashboard exposed hidden risk.

Debug branches

  • Separate quality from quantity metrics

  • enforce waiver expiry

  • run gate checklists consistently

Senior review question

Ask: what evidence proves this risk is closed for silicon, not just tool-clean?

Key takeaways

  • State crossing class, assumptions, and owner with every issue.

  • Run structural and dynamic regressions after each fix.

Common pitfalls

  • Treating all warnings as equivalent risk.

  • Waiving issues without containment evidence.

  • Skipping reset and reconvergence stress after CDC fixes.

Principal CDC/RDC review addendum

Robust CDC signoff combines structural analysis, protocol checks, reset analysis, and targeted formal/simulation evidence with consistent setup tagging.

Metric: analysis runtime, violation classification completeness, delta noise between runs

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