Thermal Dissipation Limits in High-Density Power Connectors
High-density board connectors risk thermal runaway when carrying high currents. Optimize heat dissipation with 2-oz copper and heavy thermal vias.
The ongoing push for hardware miniaturization means we are forcing more power into increasingly compact footprints. When your system layout requires running 5 to 10 amps of continuous DC power through a sub-millimeter, high-density multi-position header, you run headfirst into the strict physical laws of Joule heating (I²R). Because the internal pins of these compact connectors have minuscule cross-sectional areas, their bulk resistance—even when freshly mated—can generate significant localized heat.
If this heat cannot escape, a dangerous thermal runaway loop begins. As the temperature rises, the contact resistance of the metal pins increases, which in turn generates even more heat. Left unchecked, the temperature will quickly surpass the glass transition temperature (T_g) of the connector's plastic housing, causing the structural frame to warp, melt, or completely lose its mechanical retention force.
To design a reliable power path that keeps thermals stable, you cannot rely on the connector pins to dissipate heat into the air. The PCB itself must act as the primary heatsink. Avoid using narrow, thin traces on your power rails. Instead, connect the power and ground pins directly to wide, solid copper pours using thick, unbroken thermal ties. For current densities this high, utilize at least 2-oz (70 micrometers) copper on your external and inner power layers. Finally, drop an array of stitching vias directly adjacent to the connector pads to pull heat away from the surface and distribute it evenly across the internal ground planes of the board.