MSP430FR2522: Adhesive materials for CapTIvate MCUs

Hello Andrejs,

The first important requirement of an adhesive is to bond the PCB to the overlay material.
The second important requirement is to eliminate any air gaps between the PCB and the overlay. Air has a dielectric ~1 and can impede some of the electrode's e-field from the propagating up through the overlay. This makes the touch less sensitive.

The bonding material, much like the overlay itself, will have a dielectric > 1 (typically 3-4) and not impeded the e-field. This is why we strongly recommend always preventing any air gaps. We mention the 3M 467/468MP (PSA - pressure sensitive adhesives) because we worked with 3M to identify a common adhesive that works well and is easy to use, both for our EVM kit panel PCBs that we manufacture and for customers.

I suppose it really depends on the mechanical stack up and design of the product and your assembly process as well. So choose the type of adhesive, whether it is a PSA, epoxy or similar, just as long as it satisfies the two requirements I described above.

Does this help?

Hello Dennis,

Yes, thank you.