01PCB Thermal Analysis
How do I know if my PCB copper layout is actually spreading heat the way I assumed?
Modelling real copper pour, via stitching and trace density instead of a simplified board.
02The problem
A board layout looks thermally fine in a simplified model that treats the PCB as a uniform slab of effective conductivity, and then a hot component runs well above prediction because the copper pour that was supposed to spread its heat is broken up by routing changes, via placement, or a plane split for signal integrity.
Layout and thermal decisions are frequently made by different engineers on different schedules, so the thermal model is often built against an early or idealized version of the board rather than the ECAD data that actually ships.
Why it's hard
- Effective in-plane and through-plane conductivity of a PCB depends on actual copper weight, pour geometry and via density — not a single assumed material property
- Signal integrity and thermal requirements compete for the same copper area, and thermal is often not represented at the point layout decisions are made
- Manually rebuilding PCB copper geometry in a CFD tool from a fabrication drawing is time-consuming and error-prone
- Via stitching that improves through-plane conduction is easy to model wrong if via fill and plating thickness are not represented accurately
- Component-level power maps change late in the design cycle, and a thermal model built early is frequently stale by tape-out
03How we solve it
Predict — simulation
- Import ODB++ or IPC-2581 ECAD data directly into Flotherm or FLOEFD so the actual copper layer stack, pour and via pattern drive the thermal model
- Resolve conduction through the real copper distribution alongside convection and radiation from the board surface
Measure — hardware
- Measure component junction and case temperature on the real board with Simcenter Micred T3Ster to establish ground truth for the layout as built
Correlate — close the loop
- Compare simulated board temperature gradients against measured hotspots to confirm the copper model reflects actual layer behavior
- Feed the correlated PCB thermal model back into the enclosure or system-level model so downstream airflow decisions are built on accurate board-level physics
05Standards in scope
- IPC-2221 thermal derating inputs
- JEDEC JESD51 package characterization
07Questions engineers ask
Model your actual PCB layout, not a simplified slab.
Send us your ECAD data and the component you're worried about. We'll show you where copper spreading is helping or hurting your design.