VT Mix Strategy: Review Checklist

Review checklist

Review Checklist for VT Mix Strategy focuses on HVT/SVT/LVT cell mix, setup/hold slack distribution, leakage budget. The goal is to connect observed QoR movement to mechanism, ownership, and regression risk.

• Run manifest is attached (RTL/SDC/libs/switches).

• Primary metric and impacted lane are named.

• Mechanism hypothesis is evidence-backed.

• Fix is reversible and owner-assigned.

• Regression matrix includes timing, area, power, and equivalence as needed.

• Owners signed: synthesis owner, power owner, STA owner.

Sign-off ownership

OWNERSHIP MAP — VT Mix Strategy

artifact              owner
----------------      -----------------
compile owner       synthesis owner
timing/power owner  power owner
cross-team review   STA owner

Every QoR movement needs a named owner before ECO.

Synthesis deep dive

PPA closure is a constrained tradeoff problem, not a timing-only exercise.

Concept diagram

PPA TRIAD

timing target <-> power budget <-> area cap

Metric graph

PARETO PROGRESSION

early runs      o o
balanced point    o
over-tuned          o (risk)

Reports and artifacts

• VT mix

• leakage trend

• dynamic power trend

• PPA Pareto table

Mini case study

LVT-heavy fix recovered setup but violated leakage target; balanced VT strategy closed both.

Debug branches

• Timing-only claims need power check

• Validate hold on VT swaps

• Use Pareto memo

Senior review question

Ask: what evidence proves this QoR move is real and stable?

Key takeaways

• State exact run context (RTL, SDC, libs, switches) with every QoR claim.

• Re-run timing, area, and power regressions after each synthesis ECO.

Common pitfalls

• Comparing runs with mismatched constraints or library views.

• Timing-only fixes that violate power or area budgets.

• Skipping equivalence checks after structural changes.

Principal synthesis review addendum

VT assignment trades delay against leakage; poor mix causes either timing misses or unnecessary static power burn.

Metric: HVT/SVT/LVT cell mix, setup/hold slack distribution, leakage budget