Issue link: https://resources.pcb.cadence.com/i/1541046
24. Planning for Thermal Management: Heat Sinks, Vias, and Copper Pours How To Implement 1. Identify all major heat sources: f Check datasheets for power dissipation on regulators, power ICs, MOSFETs, LEDs, CPUs, and RF amps. f Note any parts with thermal pad requirements or specified maximum junction temperatures. 2. Use thermal relief pads and copper pours effectively: f Place large, solid copper pours (planes or polygons) under and around heat sources, tie to ground or the most appropriate net. f Use multiple, evenly spaced thermal vias to connect top and bottom pours, spreading heat into inner and opposite layers. f For components with exposed thermal pads (e.g., QFN, PowerPAK, LED), ensure direct copper connection to internal planes with multiple vias. 3. Position heat sinks and airflow zones as needed: f For high-dissipation parts, reserve board area for heat sinks or attachable thermal pads. f Align airflow from fans or vents across heat-generating zones and avoid blocking vents with tall components. 4. Keep sensitive parts away from hot zones: f Place temperature-sensitive ICs, crystals, sensors, or connectors away from major heat sources to avoid drift, derating, or failure. 5. Review stackup for thermal conductivity: f If the design is high-power or needs rapid heat spread, consider thicker copper (2 oz or more), additional ground/ power planes, or thermally conductive prepregs. 6. Simulate and measure for high-power designs: f Use thermal simulation tools to model hot spots and temperature gradients during early layout. f During prototyping, measure real temperatures with IR cameras or thermocouples and adjust layout as needed. 7. Check manufacturer recommendations: f Review package datasheets for layout-specific thermal advice: pad sizes, via counts, and recommended copper areas. Common Pitfalls, Their Impact, and How to Avoid Them Common Pitfall How to Avoid it Omitting thermal vias under hot parts Severely limits heat flow into inner/ other layers – Add an array of thermal vias beneath high-power components to dissipate heat. Too little copper under high-power devices Raises junction and board temps, risking early failure – Use larger copper pours or thermal relief pads to spread heat evenly. Placing sensitive parts near heat sources Causes functional instability and drift – Add keepouts around heat sources to maintain thermal clearance. Ignoring real airflow and environment The board layout may need to change for enclosure or system-level cooling – Validate thermal perfor- mance through simulation or prototype testing.