PCB Trace Current Capacity
In the early days the printed circuit boards were used to link the low power circuitry and high-power circuitry were made using point to point jumper wiring to compensate the high current carrying needs. As the boards evolved the copper layer is optimized by spreading it over a large space and high-resolution isolation form low power rails.
PCB trace current carrying capacity cannot surpass the good old think copper wiring but it can reduce the space consumption exponentially. The PCB trace current capacity is determined by various design aspects and material properties. For example, the most commonly use 1oz copper offers approximately 500mΩ per square inch. So, the capacity can be increased by increasing the effective are of the current path. To counteract the PCB trace current capacity the copper thickness is increased to optimize the production cost modern PCBs offers different copper thickness on a single board by which the high current paths can be isolated from the low side paths.
PCB trace current capacity is calculated during the PCB design stage and the traces are laid out accordingly. Most PCB design suits have an integrated trace width calculator or equivalent option to determine the trace thickness respective the current needs and the copper thickness of the board that is being designed. However, a more advanced simulation had to be done study the effect of high current on other circuitry and heat dissipation factors because unlike the thicker copper wire a small surge can fuse the trace resulting in a total damage of the board. PCB trace current capacity calculations must also include the integrity and power loss to predict the maximum limit and peak operation temperature.
The PCB trace current capacity calculation has to be optimized to prevent the surge in production cost of the PCB.