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I want my design to use as many common footprints as possible (eg. 0805/0603 for capacitors and resistors, powerSO8 for big switching MOSFETs, etc) so that I am less restricted by manufacturers and suppliers, and so that people in other countries etc. can build the design easier.

It appears that HC-49 is a very common footprint for crystals across a wide frequency range. I am also aware of a (less common) SMD version where it sits on a little plastic base and the leads are bent flat.

Are there any more compact SMD packages for crystals that have the broad support across many frequencies and suppliers? When I look on DigiKey it seems that all the smaller devices are in unique/manufacturer-specific packages with fairly narrow ranges of frequencies.

Am I just missing something? Is there a "go-to" package for small SMD crystals, like there is for resistors? Or perhaps a few different "go-to" packages for different frequency ranges (since lower frequency xtals probably need to be physically larger)?

(To clarify, I have no issues with reflow-only packages)

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  • \$\begingroup\$ SMD crystal Go-to Packages are only manufacturer specific. Not all the manufactures fallow same rules for SMD crystal footprint \$\endgroup\$
    – AKR
    Jun 27, 2016 at 2:39
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    \$\begingroup\$ xkcd.com/927 \$\endgroup\$
    – Tom Carpenter
    Jun 27, 2016 at 2:42
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    \$\begingroup\$ If you aren't particularly concerned about exactly meeting the parasitic capacitance requirements of your crystals, you can just make a stack of footprints that allow multiple (sizes of) devices to be soldered to the XTAL In/Out and ground. \$\endgroup\$
    – user2943160
    Jun 27, 2016 at 20:49

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There are three general SMD crystal package types in wide circulation: the HC-49/SMT, the "sideways can", and the 4 pin LCC (leadless crystal carrier).

Out of these three, the HC-49/SMT is what I would recommend for MHz crystals -- it is a gull-wing package and chunky enough to be easy to handle and solder. The downside is that it is chunky -- it's a low profile HC-49 adapted for SMT use, which makes it almost like an SMT electrolytic can size-wise.

The "sideways can" for a lack of a better name is an adapted version of existing cylindrical packages for 32.768kHz crystals, where the leads are bent for SMT mounting instead of being left straight for THT. It's the same size as the other can packages, and not terribly hard to solder; however, the can itself is mildly fiddly to handle due to the thin leads and relatively small size.

The leadless packages (i.e Leadless Crystal Carrier or DFN) are used for both kHz and MHz crystals, and come in a variety of sizes, all much smaller than the SMT versions of cylinders and HC-49s. These are generally 4-pin packages, so check footprints carefully as they are not fully standardized. They can be hand-soldered with care, but are generally used in reflow-only applications, and are not recommended for novices to hand-soldering SMT. One advantage these packages have is that they also suit 4-pin oscillators, as well as "bare" quartz crystal resonators.

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  • \$\begingroup\$ I never understand when people describe hand-soldering as easier for novices. Reflowing takes a bit more prep, but is way less "scary" than hand-soldering for me, and I don't have a lot of experience or nice equipment at all. Perhaps I will clarify in my question that reflow-only is fine. \$\endgroup\$
    – user371366
    Jun 29, 2016 at 16:19
  • \$\begingroup\$ @dn3s -- size also matters for placement purposes -- and reflow@home is probably more temperamental calibration etal wise than hand-soldering (more risk of accidental part meltdowns and such) \$\endgroup\$
    – ThreePhaseEel
    Jun 29, 2016 at 22:15
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As you have noted, HC-49 is widely available, for example on eBay. It is also a 2-lead with a bit of actual pin to hand-solder for the amateur. This is what I would go with for a hobby project to be posted online, and that sounds to me to be what you're aiming for.

For a more compact solution, Jauch oscillators would be excellent choices for reflow soldering, but I wouldn't put a solder iron to them.

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