Electronic – Does Crystal/Oscillators package matter

crystaloscillatorpackages

I design a lot of PCBs that uses microcontrollers with external clocks. For some reason a lot of the example designs always tend to use the big generic HC-49 package. Even factory made modules that I purchase tend to use that package. I typically source my components from LCSC which has a large variety of components. Are there any disadvantages to using the smaller packages for crystals other than price and availability?

Best Answer

Yes, the package can make a big difference. It's much easier to get an HC-49 crystal to start up than the equivalent HC-49S, for example. Smaller crystals will also have a lower maximum drive level, which will cause aging if you overdrive. They also have worse pullability (probably not an issue for your application). Read the crystal datasheet and make sure it matches up to what you need:

  • Will the crystal start up reliably across all conditions?
  • Will there be too much current, causing the crystal to age prematurely?
  • Does it have the frequency tolerance that your application requires? What about across temperature?