This is not a shopping question in the usual sense, because I'm not looking for specific product recommendations. I'm looking for advice on what category or style of connector is best-suited to this particular task.


I have a relatively large module, a RAC03-05SGA, that I want to be replaceable and non-soldered. As indicated in the datasheet, there are 5 pins at 200mil pitch, but they're in an irregular pattern - two pairs far apart from one another, and one pin far apart from the pairs. The pins are 0.6mm wide and 3.5mm long.

land pattern

I'm interested in getting three socket modules to accept pins 1-2, 4-5, and 3 (with the second socket beside 3 empty). Ideally, I'd also like fairly good retention force similar to that achievable by screw tightening.

Options so far

I looked at top-entry two-pin terminal blocks with screw retention to a leaf spring. These hit a lot of good points - great retention force and solid design. Unfortunately, I doubt that they're going to work, because there's almost always a significant gap between the wire entry point and the leaf spring action, so they probably wouldn't be able to grab much of the leads that are only 3.5mm long. See for example this profile view from the OSTTB 5.08mm pitch series; entry from the bottom left.


I looked at top-entry rectangular header sockets with interior finger clip. These are simple, cheap and abundant, but seem to have poor withdrawal force (typically less than 2 N). Also, they don't seem to have enough interior space for the leads, with a little over 2mm. (I could snip the leads to make them fit, but I'm not in love with that idea.) See for example the Preci-Dip 801 or 310 series. Finally, it's doubtful that these are well-suited to round leads; they seem designed for rectangular pins.

I found an odd-ball product filed under IC sockets, though it doesn't look like an IC socket - you can get single-pin solderless press-fit "IC sockets" that have 150mil (3.8mm) of interior space; see for example the 346 series from Mill-Max:


The size of pin seems appropriate - 0.6mm is 23.6mil, which is within the 25mil pin width indicated by the spec. However, it doesn't give any data on retention.

Promising but difficult-to-find is a device somewhat similar to a terminal block - a right-angle barrier strip with screwed captive plate, such as the TE 4DB-R108. The pitch is technically wrong, but the gaps are big enough that the leads might fit:

barrier strip

What style of socket would work best here?

  • 2
    \$\begingroup\$ Mill-max makes a soldered-in version of that, too. If retention is an issue, either do some testing, or make holes to either side of the module and hold it down with a zip-tie. \$\endgroup\$ – TimWescott Mar 7 at 2:06
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    \$\begingroup\$ Those power supplies are really made to be soldered. Why are you trying to avoid that? If you're playing around with prototypes you could probably hack together something like an old relay socket with some individual pin sockets, a 3d printer and a retention strap or bail, but it seems like a bad idea in general. \$\endgroup\$ – Chris Stratton Mar 7 at 2:25
  • \$\begingroup\$ You can also use standard non-press fit machined socket pins. They come in many contact diameter ranges. Just put the right hole spacing in the PC board, put the pins on the part, place the part in the board, and solder the pins. Just make sure to use closed bottom pins so that solder can not wick into the contact area. \$\endgroup\$ – crj11 Mar 7 at 2:33
  • \$\begingroup\$ Seconding Chris, why not just solder them? \$\endgroup\$ – Hearth Mar 7 at 2:36
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    \$\begingroup\$ mount the module on a carrier PCB with mounting standoffs and connectors designed for daughter cards ........... mouser.ca/Connectors/Board-to-Board-Mezzanine-Connectors/_/… \$\endgroup\$ – jsotola Mar 7 at 2:47

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