PCB Assembly Services – Screaming Circuits: Edge Mount Rf Connectors

Some parts just look cooler than others. I really like the super tiny WLCSP (wafer level chip scale package) BGAs that some newer ARM microcontroller and power components come in. They not only fit the “smaller is cooler” mantra, but they are shiny and reflective under the right conditions.

Another one of my favorites is the edge mount high speed RF connector. I’m not sure why, but I just like the look of them. 

Unfortunately, “I like the look” doesn’t necessarily translate to “it is easy to build.” The WLCSP, for example, takes special precautions for the footprint, as does the aforementioned connector. The edge mount connector requires a proper footprint and a match with the PC board thickness.

SNA edge conector LABELED

The center pin needs to be flush with the board surface, so if the board is too thin, the assembler will have to use extra caution to ensure that the air gap is on the back side of your board. Doing so will reduce the mechanical strength of the connection. To prevent that from happening, these parts come in multiple varieties to accommodate different board thicknesses. Whenever possible, match the opening of the connector, labeled “Board Thick” in this table from a Cinch Connectivity datasheet.

Cinch Connectivity RF edge mount  connector

If the PC board is too thick for the particular variant of connector, you probably won’t be able to put the connector on. If the board is thinner, you, us or whomever is assembling it will have to take extra care to ensure a solid and straight connection. Any air gap on the solder side will need to be filled with solder, which can change the signal propagation characteristics of the connection.

Some of these connectors will only have one or two board thickness options, some more, so you may not be able to match your board thickness exactly. But, if you can, you will end up with a more reliable and robust installation. Just make sure you also follow the electrical and footprint guidance in the component datasheet.

Duane Benson
Be sure to watch Captain Rf, hero of electromagnetic wave propagation
Coming soon to theaters near you


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