Thermal simulation cuts potting costs in half

The Flopack web-based wizard quickly produces accurate models of integrated circuits and other components.

C-Mac MicroTechnology used Flomerics' Flotherm thermal simulation software to determine that the thermal requirements of a stacked module could be met with a potting compound that cost only half the amount of the default choice.

"Our engineer simulated the junction temperatures of the devices in the stacked modules while using three different potting compounds", said Bob Hunt, Head of Engineering for C-Mac.

"Simulation was much faster and less expensive than the alternative of building and testing prototypes".

C-Mac recently developed a stacked module for a critical defence application.

Prior to building prototypes, C-Mac engineers performed thermal simulation on the initial concept design and discovered that junction temperatures on the module ranged up to 125C, well above the 100C maximum.

They realised they needed a potting compound to reduce thermal resistance and wanted to select the least expensive formulation that would meet the thermal requirements of the application.

"Without simulation we would have been faced with two unattractive alternatives", said C-MAC Senior Engineer Jonathan Crossley.

"We could have undertaken a much lengthier and more expensive physical testing process to identify the potting compound that provided the best mix of performance and price".

"Or we could have foregone this process and used the best potting compound because we were fairly confident that it would have delivered acceptable thermal performance".

Instead, Crossley performed thermal simulation on the initial design using Flotherm software.

"We use Flotherm because it provides many built-in functions that reduce the time required to module complex stacked module designs", Crossley said.

"The most important of these is the Flopack web-based wizard, which quickly produces accurate models of integrated circuits and other components".

Crossley used the Flomerics Flopack web-based wizard to generate models of each of the components.

"Using the Flopack wizard all I had to do was enter basic design parameters such as the die size, die flag size and lead frame clearance".

"Flopack generated models of the components that were almost complete".

"I was able to create a thermal model for this stacked module with Flopack in a tenth of the time that would have been required using conventional modeling methods".

Crossley ran thermal simulations of the stacked module with three different potting compounds.

Hunt said "Thermal simulation helped us engineer an optimised solution while minimising our engineering costs and leadtime".

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