â–¼

Selecting a Circuit Layer

â–¼ Current Carrying Capabilities
â–¼ Heat Spreading Capabilities
â–¼ Flatness In Relationship To Thickness

Current Carrying Capabilities

The circuit layer is the component-mounting layer in ThermalClad. Current carrying capability is a key consideration because this layer typically serves as a printed circuit, interconnecting the components of the assembly. The advantage of Thermal Clad is that the circuit trace interconnecting components can carry higher currentsbecause of its ability to dissipate heat due to I 2 R loss in thecopper circuitry.The following equation can be used to calculate minimum tracewidth utilizing both circuit thickness and current requirements. CalculatingMinimumTraceWidth
1 /
2 W
C =

[ ]

T
2 S I R
S 2 K +T
S -T
S S T
RISE where: W
C =Conductor Width (meters)T
S =Dielectric Thickness (meters)I=Current (Amps)R 1.78 x 10
-8 Ω •mT
S =Circuit Sheet ResistivityT
C C =Foil Thickness (meters)K
Bergquist Dielectric LTI current capability with known trace width and aseries of circuit thicknesses. Additional charts regarding our other dielectrics are also available. Example of FR-4 current capability with known trace width and a series ofcircuit thicknesses. Comparison of Bergquist Dielectric LTI and FR-4 current capability. S =Thermal Conductivity of the Dielectric(W/m-K)T
RISE =Allowable Temperature Rise (K)
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