Conclusion

AN3232

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Doc ID 17594 Rev 3

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Conclusion

This application note provides a set of guidelines to be considered for the proper attachment

of STAC packages. While these recommendations are intended to address the majority of

user applications, the flexibility afforded by this new generation of package technology

enables new approaches for amplifier assembly as well as novel system architectures. In

the search for constant improvement, ST continues to address customer needs by

improving the robustness of the STAC package line and by releasing additional outlines with

more functionality and versatility. For these reasons, it is expected that these guidelines are

to be revisited and updated over time. At present, these recommendations are expected to

result in reliable mechanical, electrical, and thermal performance.

Regarding the thermal expectations of STAC packages, this application note demonstrates

the exceptional performance that can be attained when utilizing the solder-down mounting

method; this can be viewed as the limiting case for lowest achievable thermal resistance.

While the STAC package concept embodies highly customizable thermal solutions by

means of chip carrier material substitution, the importance of an exceptionally low thermal

the case presented, this interface accounts for only 0.025 °C/W, roughly half of what is

achievable with industry standard flanged packages. In this regard, STAC packages afford

intrinsic flatness and the highest available thermal conductivity materials, further enhancing

cooling efficiency. Even without soldering, judicious selection of TIMS and respect to this set