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Using Thermal Clad Dielectric Material...

Two-Layer Systems Using FR-4 Circuits orThermal Clad Circuits

Bergquist dielectrics are ideal for applications requiring a two-layersolution. Two-layer constructions can provide shielding protection and additional electrical interconnects for higher component density. In conjunction with FR-4 type circuits or Thermal Clad circuit pairs, Bergquist dielectrics will provide superior thermal performance over traditional FR-4 constructions. In addition, thermal vias can maximize thermal capabilities for applications utilizing power components. When vias can not be used, selecting higher performance dielectrics can solve thermal issues independently (see adjacent graph).

The graph depicts the modeled thermal result of various two-layer constructions as a function of device case temperature. The emphasis is the thermal effect of proper via utilization. The picture above represents the construction of a two-layer circuit material bonded withBergquist dielectrics to a metal base. These configurations utilize either Thermal Clad circuit or FR-4 type circuit materials, depending on the thermal requirements and cost objectives. The configuration pictured above is that of a two-layer circuit pair, however, multi-layer constructions are also available on copper base material. Thermal Vias Exposed Circuit Layer
Thermal Vias Cross Section Internal Circuit Layer BaseThermally Conductive Dielectric
Thermal Vias Plane View

Single Board SolutionsWithout The Metal Base

The thermal performance of Thermal Clad dielectrics are oftensufficient to handle thermal requirements, thus eliminating the need for a metal base layer. In addition, the current carrying capability is often improved enough to reduce the thickness requirement. See Selecting a Circuit Layer section on pages 14-15 for additional information.With the elimination of the metal base, components can bemounted on both sides. This can often create a single board solutionwhere the power components are no longer separate from the logic components as is the case in a two-board system. 10