vyges-thermal — on-chip thermal

Part of the Vyges Loom suite. Install once with vyges install loom, then run vyges loom thermal. It’s also a standalone vyges-thermal binary on your PATH (the integration contract for flow authors).

vyges-thermal lands the design’s power on the die as heat and solves the steady state — reporting the peak temperature, the hotspot location, per-block temperatures, and a PASS/FAIL against a temperature limit. It is the thermal dual of vyges-em-ir: the same grid solve, temperature where em-ir has voltage. The per-block power comes from vyges-power; with temperature-dependent leakage it runs the electro-thermal loop to a fixed point (leakage heats the die, the hotter die leaks more), so you get the real operating temperature — closing char → power → em-ir → thermal → power.

Run it

vyges install loom                                       # one-time: fetch the Loom suite
vyges loom thermal demo                                  # instant: built-in floorplan → temp + heat map
vyges loom thermal run  block.thermal -o block.rpt       # analyze → report
vyges loom thermal run  block.thermal --fail-on-violation # exit 3 if over the limit (CI gate)
vyges loom thermal check block.thermal                    # validate the job

Job file

A .thermal job declares the die, the solver grid, the material parameters (k_si, thickness_um, theta_ja), the ambient, and the temperature limit; a floorplan: (.flp) places the blocks and their power (with an optional per-block leakage portion for the coupling). Standard CLI: --json, --quiet, --verbose — and like the rest of the suite it fails CI (exit 3) when the peak exceeds t_limit_c.

See the CLI reference for the full flag list, and Job-file formats for the .thermal / .flp shapes.

Digital and analog / mixed-signal

The solve is G_th·ΔT = P on a tile grid built from a generic .flp block list — each block is just name x y w h power, with no notion of where the power came from. It is fully decoupled from the power source, so an analog / mixed-signal floorplan lands its heat and solves exactly as a digital one does. The examples/pa/ job is an RF power-amplifier floorplan whose concentrated dissipation produces a classic analog PA hotspot.

vyges loom thermal run examples/pa/pa.thermal   # RF power-amplifier floorplan → temp + PA hotspot

Heat flow is heat flow; the block powers can come from digital activity or an analog op-point. Scope here is physical thermal analysis; analog functional / timing sign-off is out of scope (that leans on external SPICE / behavioral tools).

Correlation baseline: HotSpot (the canonical open on-chip thermal simulator) — there is no thermal tool inside OpenLane/OpenROAD, so vyges-thermal fills that gap.