What is a flex PCB?

A flexible printed circuit board, also known as a flex PCB, is an electronic circuit that is built on a flexible substrate, allowing the board to bend, fold or twist during use. Unlike traditional rigid PCBs, flex PCBs are designed to fit into compact, lightweight and dynamically moving electronic products. Flex PCBs are widely used in modern electronics such as smartphones, wearables, medical devices, automotive systems and aerospace applications, where the ability to flex is required and space, weight and reliability are critical.

A study shows how high-thermal dielectrics outperform FR-4 for bulk heat spreading, with surface-mount thermal bridges serving as targeted tools for hotspot control.

As power density continues to increase across power electronics, industrial controls, automotive electrification and data center infrastructure, printed circuit boards (PCBs) are increasingly required to function as active thermal management structures rather than passive interconnect platforms. Localized hotspots, rising junction temperatures and constrained form factors are pushing conventional FR-4 substrates beyond their practical thermal limits. In response, PCB designers are adopting a combination of material-level improvements within the PCB stackup and localized heat-spreading solutions. One such approach is the use of surface-mount thermal bridges (SMTBs), passive SMT components designed to conduct heat away from power devices and redistribute it into larger copper regions of the PCB without providing an electrical function.