behavioral-modeling

Skill: Behavioral / AMS Modeling

Invocation

• If invoked by a user presenting a modeling task: immediately spawn the analog-chip-design-agents:behavioral-modeling-orchestrator agent and pass the full user request and any available context. Do not execute stages directly.
• If invoked by the behavioral-modeling-orchestrator mid-flow (including fix-request servicing): do not spawn a new agent. Treat this file as read-only — return the requested stage rules, sign-off criteria, or loop-back guidance.

Spawning the orchestrator from within an active orchestrator run causes recursive delegation and must never happen.

Pre-run Context

Before executing or advising on any stage, read the following if they exist:

1. memory/modeling/knowledge.md — known Verilog-A idioms, OpenVAF/ADMS quirks, convergence recipes, RNM pitfalls. Incorporate its guidance into every authoring decision.
2. memory/modeling/run_state.md — current run identity (run_id, design_name, pdk, last_stage) for resume-after-interruption.

Purpose

Author, compile, and validate analog behavioral models and the connect modules that bridge analog and digital domains — the "analog HDL" capability. Six stages with explicit QoR gates and loop-back criteria enforced by the behavioral-modeling orchestrator. A model is only signed off when it is both accurate (vs a SPICE reference) and faster than SPICE.

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Supported EDA Tools

Open-Source

• OpenVAF (openvaf) — Verilog-A → OSDI compiler for ngspice / Xyce; the primary path
• ADMS (admsXml) — legacy Verilog-A → C model generation
• ngspice (ngspice) / Xyce (Xyce) — OSDI loading + model-vs-SPICE co-sim
• SystemVerilog RNM (nettype/wreal) via Verilator (verilator) / Icarus (iverilog)
• Hdl21 + VLSIR (python -m hdl21) — programmatic (Python) analog HDL
• GHDL-AMS (ghdl) — limited VHDL-AMS support

Proprietary (detect-only — never installed)

• Cadence AMS Designer / Xcelium AMS (xrun) — Verilog-AMS / Verilog-A reference
• Spectre Verilog-A (spectre) — Verilog-A in Spectre
• Synopsys VCS-AMS / CustomSim (vcs) — AMS co-sim
• Siemens Symphony / Symphony Pro — AMS simulation