The model below calculates the relationship between current
and temperature rise. It comes from UltraCAD,
(Temperature Rise in PCB Traces Eq. 11). The origin of this model
is presented in the article in Design News, Vol. 23, from the
6 December 1969. The article describes the experiments of leading
current through copper traces in different sizes. The results
were adapted to the mathematical functions, that are used here.
Give the known parameters below and push the Calculate button.
The trace is placed in an:
A trace with the length of cm will have a potential drop of V and a resistance of ohm.
Note: When producing a multilayer PCB the tolerances of the trace thickness
are normally quite large in the outer layer. This implicates that
it is difficult to get traces with exact resistances in the outer
layer. On the other hand, leading current in an inner layer can
entail cooling difficulties. (FR4-laminate transforms into electric
conducting graphite at overheating. This can result in a short-circuit.)
At transients the trace must be prevented to be as hot by the current
as the metal melts.
Increase of temperature:[°C]
Width of trace: [mm]
Thickness of trace:[um]
Transient time: [sec]
Current carrying capacity: [Ampere]
Increase of temperature: [°C]
Board thickness: [mm]
Diameter of the via:[mm]
* Rule of thumb: A microvia corresponds at least a trace with
the width 4mil=0.1mm, the thickness 13um and stands a current
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