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One of the most common outputs from a DC Drop simulation is a current density plot. But how much is too much current density? The answer depends on temperature rise, and requires a PI-thermal co-simulation to properly characterize.
HyperLynx PI does an iterative co-simulation to include the effects of current density on temperature rise, and the effect of temperature on current density and voltage drop, to quickly pinpoint problems in your PCB's power distribution network. This new video explains how designers can keep their PDS from feeling the heat.
To view this video, click here.
Alistair Little, Electrolube
This month, I’m going to cut through some of the more heavy-going tech-speak, taking a few of my customers’ more frequently asked questions about resins to try to help you refine your selection process. There’s a lot of ground to cover, but for the purposes of this column, let’s concentrate on the PCB’s operating environment, caring for the components that are to be encapsulated, and the special needs of applications like LED lighting and RF systems.
John Coonrod, Rogers Corporation
Coefficient of thermal expansion (CTE) is typically considered for PCB reliability, but it can also have an impact on circuit performance for applications exposed to varying temperatures. Due to CTE, a circuit will change physical dimensions when the temperature changes. If the circuit has small features or tightly coupled features, the physical change of the circuit dimensions can cause a shift in electrical performance.
Douglas G. Brooks, PhD
The reasons for the temperature variation at high temperatures are not too hard to understand. There may be minor contamination under the trace or in the copper that accounts for it. Certainly, at higher temperatures (say above about 300°C) the board may begin to delaminate, severely disrupting its cooling characteristics. There may be small variations in trace width or thickness that help account for the delam, and these effects would be randomly distributed along the length of the trace.