New-Tech Europe | September 2016 | Digital Edition

Figure 2: hermetically sealed cavity packages.

Figure 1: plastic encapsulated MMIC devices.

contact of the cleaning solution and the customer’s conformal coat with the unit’s sensitive circuitry. This pre-coating has been qualified to withstand the conditions of customer reflow, aqueous wash, and conformal coating processes without failures or shifts in RF performance. The pre-coating seals the sensitive areas of the unit such that during the customer’s reflow process, there is no wicking of solder or creation of solder balls in the sealed structure, which would otherwise cause reliability problems. This economical technique can be used to adapt open or semi-sealed surface-mount components in Mini-Circuits’ catalog to preserve reliability in hi-rel assembly processes for minimal increase in cost. Conclusion: The trend toward aqueous wash and conformal coating in hi-rel applications means components that were once universally used will be increasingly unsuitable for integration into customer assembly processes in their standard form. Fortunately, Mini-Circuits has now developed a cost-effective approach to adapt non-sealed surface mount components for outstanding reliability in customer assembly processes involving aqueous wash and conformal coating. This gives customers the freedom to select components without limitations based on case style. Open and semi-sealed parts may be adapted for customers utilizing aqueous wash and conformal coating without adding inordinate cost or complexity to their board design or assembly process.

Figure 3: semi-sealed and open component assemblies

Figure 4: Pre-coating on air coil legs.

Figure 5: Pre- coating on weld spot

Figure 6: Pre- coating on inductor.

to make hermetically sealed packages for larger structures. Therefore an alternative technique to adapt open and semi-sealed surface mount components for hi-rel assembly without adding extraneous cost or technical inconvenience to the process is highly desirable. In response to customer requirements for open and semi-sealed components in our catalog for systems undergoing hi-rel assembly processes, Mini-Circuits developed a proprietary sealing method to protect these components during the aqueous wash process and enable them to operate reliably within the customer conformal coat. A special pre-coating is applied to certain areas of the Mini- Circuits unit, which prevents direct

the dielectric properties of the circuit, resulting in shifts in RF performance. For example, mixers and limiters are generally unaffected by contact with conformal coating, whereas VCOs and diplexers are sensitive and unsuitable for conformal coating unless contained in a sealed case. The Solution: Proprietary Sealing Method In an ideal world, we would simply adopt hermetically sealed cavity packaging for everything to withstand customers’ assembly processes, but there are practical limits to this solution. Hermetic packaging adds significant cost to the component, and it is highly impractical

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