Issue link: https://iconnect007.uberflip.com/i/1487920
46 DESIGN007 MAGAZINE I DECEMBER 2022 As technology advances, thermal expecta- tions are becoming more critical, and design- ers need to be aware of the many aspects that can alter the performance of a circuit due to thermal issues. ermal concerns can be dif- ferent for digital applications vs. RF applica- tions, and when DC or AC power is included, they can further complicate the matter. ermal management is a very broad term for many potential thermal concerns for PCBs. Probably the most common reference to thermal management is related to keeping the circuit temperature below a critical limit by considering the many variables that can impact circuit heating. However, there are other thermal issues which can impact the RF or digital performance of a circuit. ermal Optimum Thermal Stability Considerations coefficient of dielectric constant (TCDK) is a property that all materials have, and it is char- acterized by how much the Dk of the mate- rial will change given a change in tempera- ture. ere are also related properties such as thermal coefficient of dissipation factor (TCDf ) and thermal coefficient of insertion loss (TCIL). e TCDf and TCIL relate to how much the Df or the insertion loss can change given a change in temperature, respectively. Addition- ally, a circuit performance change due to aging can be significantly impacted by the thermal behavior of the circuit and its operating envi- ronment. Finally, moisture absorption is nor- mally not considered as part of thermal man- agement concerns, but it can be. Lightning Speed Laminates by John Coonrod, ROGERS CORPORATION