OCV / AOCV / POCV Mechanisms: Review Checklist

Review checklist

Review Checklist for OCV / AOCV / POCV Mechanisms focuses on OCV derate %, depth-adjusted pessimism, POCV sigma contribution. The goal is to connect the observable symptom to timing mechanism, ownership, and regression risk.

• SDC revision and implemented clock/exception policy are named.

• Clock/reset and CDC assumptions are reviewed.

• Path groups, IO delays, and exception rationale are documented.

• MMMC scenario list maps back to signoff requirements.

• WNS/TNS artifact stored with corner/mode/view tags.

• Owners signed: STA lead, library team, foundry interface.

Sign-off ownership

OWNERSHIP MAP — OCV / AOCV / POCV Mechanisms

artifact              owner
----------------      -----------------
timing report       STA lead
SDC/constraint      library team
implementation      foundry interface

Every WNS cluster needs a named owner before ECO.

STA deep dive

Variation policy is negotiated margin, not a tool checkbox.

Concept diagram

VARIATION STACK

nominal delay + OCV/AOCV/POCV margin = signoff delay

Metric graph

DERATE IMPACT ON WNS

OCV only     WNS -120ps
AOCV         WNS -45ps
POCV         WNS -60ps (policy dependent)

Reports and artifacts

• derate table

• AOCV depth report

• POCV sigma

• hold/setup split

Mini case study

Switched to AOCV without re-baselining hold — short paths failed min analysis.

Debug branches

• Short paths for hold

• Policy approval for derate changes

Senior review question

Ask: what corner/mode/view proves this topic is closed or failing?

Key takeaways

• State corner, mode, view, and database tag with every slack claim.

• Run setup and hold plus MMMC regression after every ECO.

Common pitfalls

• Comparing STA runs with different SPEF or SDC tags.

• Broad false_path to green-wash violations.

• Setup-only ECO without hold check.

Principal STA review addendum

Variation models add margin for on-chip delay spread; AOCV/POCV reduce over-pessimism by accounting for path depth and statistical correlation.

Metric: OCV derate %, depth-adjusted pessimism, POCV sigma contribution