Run a configured SPEF RC analysis

Use a Cloud 2.1.2.10 project or a Local project in Digital Design Studio for Windows 2.1.2.3. Sign in with an active paid plan and select an organization with access to SPEF computation. The calculation runs on this device.

Prepare the saved inputs

Save your SPEF file as inputs/design.spef. Prepare inputs/spef-analysis.json with the configuration below. Use net and node names from your SPEF in elmore and irDrop, and set the load currents in amperes.

Choose spef_minimum, spef_typical or spef_maximum in corner.model for min:typ:max parasitics. Use single_caller_resolved for scalar parasitic values. Save the configuration before running.

{
  "schema": "altifigence.px.spef-configured-analysis-config.v1",
  "version": 1,
  "spefArtifactId": "my-spef-input",
  "corner": {
    "model": "spef_typical",
    "name": "Typical parasitics"
  },
  "units": {
    "capacitance": "farad",
    "resistance": "ohm",
    "current": "ampere",
    "time": "second",
    "voltage": "volt"
  },
  "assumptions": {
    "couplingCapacitance": "reported_not_folded_into_elmore_load",
    "elmoreTopology": "connected_resistor_tree",
    "irDrop": "static_linear_resistor_network"
  },
  "elmore": {
    "net": "power",
    "root": "power:src",
    "target": "power:load"
  },
  "irDrop": {
    "net": "power",
    "ground": "power:src",
    "currents": [
      {
        "node": "power:load",
        "currentA": 0.001
      }
    ]
  }
}

Run the analysis

1. In Flow Navigator, expand Analysis and choose SPEF RC analysis.

2. Enter the saved SPEF path in SPEF input and the configuration path in Configured-analysis JSON.

3. Choose Run configured analysis.

4. Read Elmore delay in seconds and Maximum IR drop in volts. Check Corner and the Elmore and IR-drop net details against your configuration.