Q: What thermal management techniques should be used for high-power PCB components?
Answer
For power components: (1) Maximize copper area on the pad and surrounding ground pour. Use thermal vias (0.3-0.5 mm diameter 1 mm pitch) to connect top layer copper to inner GND or bottom layer. (2) For >1 W dissipation use a heat spreader (aluminum core PCB or copper coin insert). (3) Calculate thermal resistance: theta_JA = theta_JC + theta_CS + theta_SA. Keep junction temperature below 125C for most semiconductors. (4) Place thermal reliefs (spoked connections) between pad and copper pour. (5) For motors use separate thermal zones. Use thermal simulation in Altium/Fusion 360. In free air 1 sq inch of copper ~35 C/W; with thermal vias it drops to ~15 C/W.
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