STA Mastery · All levels
STA Metrics Reference
Common metrics for timing closure and signoff.
Core metric families
Closure: WNS, TNS, failing endpoint count, path group WNS.
Constraints: clock skew, uncertainty, exception count, IO coverage.
MMMC: per-corner WNS, scenario worst-case, view delta.
Variation/SI: derate %, delta delay, noise peak, hold/setup split.
ECO: pre/post WNS, leakage delta, regression pass rate.
diagram
METRIC GRAPH — WNS / TNS / hold WNS
WNS (ps)
^
| target (0)
| - - - - - - -
| o after ECO + hold check
| o
| o baseline run
| o failing regression
+--------------------------------------> closure iteration
view audit path group fix MMMC signoff
Readout:
- explain why WNS/TNS moved and which path group drove the change