I have come across these rather big connectors on Altera trasciever boards in particular. I was wondering what is special about them.

  • \$\begingroup\$ If you are designing a new product, need to reduce footprint size as the question hints at, and have control over both ends of the RF connector, then options like SSMA (up to 40 GHz) or UMCC (up to 6 GHz) exist with the same 50 Ohm impedance. \$\endgroup\$ May 3, 2013 at 10:54
  • 1
    \$\begingroup\$ Or UFL: en.wikipedia.org/wiki/Hirose_U.FL \$\endgroup\$
    – pjc50
    May 3, 2013 at 10:58
  • 4
    \$\begingroup\$ Do you have a picture? SMA connectors are "rather small" when compared to BNC connectors, so I'm not sure you are seeing the type of connector you think you are seeing. \$\endgroup\$
    – The Photon
    May 3, 2013 at 16:26

2 Answers 2


This is an example of SMA plug and jack connectors:

enter image description here

Most often, the plug type (left) is used on cables and the jack type (right) is used on instrument panels or pcbs.

SMA connectors are:

  • Small relative to connectors that preceded them, like BNC and N types.
  • Suitable for use at frequencies up to 18 GHz.
  • Widely used in industry for those frequencies.
  • Quite robust against vibration, repeated insertions, and other abuse (when a proper torque wrenche is used)
  • Available at reasonable prices (e.g. on the order of $5 per connector)
  • Available on a wide range of coaxial cable types.

It's a minature coax connector, used for connecting coaxial cable or antennas. This design is required for high-frequency single-ended signals. They're designed to have a characteristic impedance that is a reliable 50 ohms across a fairly wide range of frequencies.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.