Core capabilities
- Coupling coverage analysis: Compute coupling capacitance coverage and crosstalk risk from routing geometry.
- SI risk detection: Flag nets exceeding coupling noise thresholds; output risk scores and affected paths.
- Routing-stage mitigation: Provide guides during iRT detailed routing—increase spacing, insert shields, adjust route order.
- Noise propagation modeling: Reuse iSTA crosstalk propagation for aggressor–victim delta-delay estimates.
- Agent-ready: Python API analyzes design snapshots and returns structured risk lists and mitigation suggestions.
Agent calling patterns
si = client.call("iSI.analyze",
design_ref="snap_7f3a",
scenario="func_worst"
)
# si.coupling_coverage → float (0-1, coupling coverage)
# si.si_risks → list[dict] (at-risk net list)
# si.mitigation → list[dict] (mitigation: net, action, expected_improvement)Input / output contract
| Direction | Parameter | Type | Description |
|---|---|---|---|
| Input | design_ref | str | Post-route design snapshot (includes geometry) |
| Input | scenario | str | Analysis scenario: func_worst | func_typical | test_mode |
| Input | threshold | float (optional) | Coupling noise threshold (mV); default from library recommendation |
| Output | coupling_coverage | float | Fraction of nets analyzed vs. total |
| Output | si_risks | list | Risk net details: net_name, aggressors, noise_margin, risk_level |
| Output | mitigation | list | Mitigation: net, action (shield/spacing/reroute), expected_improvement |
Role in the flow
01 Physical design
iFP · iPL · iCTS
Placement & clock tree
02 Route
iRT
Global & detailed routing
03 SI analysis
iSI
Coupling/crosstalk risk analysis
04 Timing signoff
iSTA · iTO
Timing signoff including SI effects
iSI runs after routing and before timing signoff. It extracts coupling from route geometry, identifies SI risks, and feeds results to iSTA for crosstalk-aware timing analysis.
Related resources
- iSTA — Static timing analysis: Crosstalk propagation foundation; SI results feed final timing signoff.
- iRT — Global & detailed routing: SI data source (route geometry) and mitigation target.
- EDA tools overview: Map of all 22 point tools.