PCB Material Data Sheets

For all of our friends that feel just a little uncertain when material data sheets are discussed and words like dielectric constant, Tg and  coefficient of thermal expansion are thrown into the discussion, we have compiled a short cheat sheet just for you.

Dk – Dielectric Constant – The way the electrical signal moves through the material from front to back.
Dissipation Factor – Loss Tangent – How much the signal dissipates or “leaks” out of the substrate.  The higher the speed, the higher the losses.
Coefficient of Thermal Expansion – Thermal fractional change in material for unit change in temperature.
Resistivity:  How strongly the material resists a current.
Tensile Strength:  Relates to the rigidity of the material as well as the peel strength.  How far can the material be stretched before permanent damage occurs.
Dimensional Stability:  The tendency of material  to change in the x and y dimensions when copper is etched away from the dielectric material or when exposed to temperature extremes.
Tg – Glass Transition Temperature – Temperature that material exhibits a change in physical characteristics. The resin changes from rigid or hard to a soft, rubber like material.
Td  – Thermal Decomposition Temperature – Temperature at which the material weight changes by 5%.  This parameter determines the thermal survivability of the resin material.
 
As always, if you have questions or would like additional information, please contact us!
Purchasing and designing printed circuit boards does not have to be difficult!
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