Precautions When Using Chip Resistors
Factors that Affect TCR ②
Factor ② Copper Foil Thickness
In some cases, it may be necessary to increase the thickness of the copper foil on the PCB, for example to carry a larger current or improve heat dissipation, but as the copper foil becomes thicker the TCR of the copper material must be added, which has a significant effect on the TCR of the land pattern.
For shunt resistors with ultra-low resistances of 10mΩ or less, the copper material accounts for a larger percentage of the resistance value, so the effects of the TCR must be considered.
The following shows the relationship between PCB copper foil thickness and TCR, using a 0.3mΩ PCR100 as an example.
You can see that the TCR varies with copper foil thickness.