Sometimes when browsing through SMA connector products, you may come across a device like R222723120 which mentions that it must be mated to a “full detent”, “limited detent”, or “smooth bore” SMA connection. How do each of these differ from a regular SMA connection, and what do they do?
Detents in SMA connectors are there to improve retention and provide positive lock to an SMA mating pair. A full detent SMA connector is a male SMA device that has an undercut which properly designed females snap into, allowing for a positive lock to aid in maintaining connection in rough conditions. This has the drawback of significantly increasing the required mating force of the connector, which can be beneficial in some cases but elevates the risk of damaging the board if care is not taken when mating the product.
Smoothbore connectors lack this undercut and are held in place only by friction. These connectors have much lower mating forces, making them suitable when many mating/unmating cycles are expected or when one wants to minimize mating forces for mass fabrication in devices not intended to move much, but they clearly suffer from weaker connection retention.
A limited detent part is a compromise between these two, with a less pronounced undercut that still offers some degree of extra retention while keeping mating force below that found in full detent parts.