So I’m tying to make a small MEGA32U4 module similar to this and I cannot find the footprint for the small crystal/resonator I need. Do you know which one it is?
Also, I got the schematic for this module but it’s on Eagle version, is this the correct Kicad equivalent?
The symbol is OK and is less important than the footprint. For that you need to link to the data sheet of the one YOU will be using.
That’s what I’m looking for, I WANT to use the same than in the first picture, I don’t know which one it’s. I don’t know which one it is to assign the footprint or how to find it on google in case it’s not in the Kicad footprint library
If you don’t know what that part is, how will you ever be able to purchase it? Find a part that you can purchase that has the specs for what you want and then you can figure out the footprint. (Note, you may have to make the footprint after all, as extensive as KiCad’s provided libraries are, it isn’t all inclusive to every possible part on the market.)
3 terminal ceramic resonators come from Murata and many others, search Digikey to find suppliers.
For a new design, you might like to select a ‘better’ resonator like Murata CSTNE8M00GH5L000R0
For footprints, under Cystals library, Resonator_SMD… has a few hits, as a starting point.
You may find they need to be shrunk a little, but starting with one broadly ok, and tweaking pad XY can be faster than starting from blank page.
WHY is this not STUPID obvious?
^^^Serious question!^^^
@utig is there some reason why you would rather spend hours looking for a Footprint VS just spending the time to learn KiCad to create the properly specified Footprint in the DataSheet after you source a part?
As Sprig already pointed out. Secure the part in question first. Then make your footprint and a 3d shape as well.
Murata is a good starter.
Then again, crystals are quite small these days, easily to come by, and there are already some useable footprints available. Only caveat is two additional capacitors. Apart from that crystals tend to be more accurate.
Regrading symbol: The eagle symbol only has two pins. why use the shielded symbol from kicads library that has 3? This will not work if your part is not shielded in reality.
Regarding footprint: well it is very unlikely that you will always be able to find one made by somebody else for your component. And even if you do you still need to check it for correctness. So you might just want to learn how to make footprints. Look here as a start: Tutorial: How to make a footprint in KiCad 5.1.x (From scratch)?
I read the Eagle symbol as having the two caps integrated. (The crystal symbol, caps, and all connecting lines appear to be all the same color red. The connections to the labels and ground symbol are green.) I don’t often search for these type of parts, so I don’t know how common (or not) integrated caps are for crystal resonators with more than two leads. I wasn’t sure if the KiCad symbol was indicating a shield, or if that was another way to indicate integrated capacitance. (Which is why I didn’t comment on this before.)
I have used the three terminal variant, where the centre pad is the capacitor common/ground. It is NOT a shield.
These are were popular in consumer products, where a HC-49 crystal would be bigger than a smd microcontroller. The lower price is attractive and ceramic resonators are more robust than crystals.
The downside is lower Q and poor stability.
RS PRO 8MHz Crystal ±20ppm SMT 4-Pin 3.2 x 2.5 x 0.7mm does not seem to be a problem.
If you go higher in frequency you can get away with a 2x1.6 mm case, or even smaller. Though make sure you match the two capacitors to the crystal and micro-controller’s crystal pins.
Ceramic Resonators with 3 leads, invariably include the caps.
Ceramic resonators with 2 leads, have no caps included.
Yes, the Eagle symbol is clearer to what actually occurs, but the KiCad symbol is tolerable as the final part is 3 terminals, and the Resonator footprints I indicated above have pin 2 as the centre pin, so it will map ok.
Earlier, I hadn’t looked into the KiCad library to see if the OP had selected the wrong symbol in KiCad… When searching for crystals, I find what he had found (with various pins for the ground:
Then I thought to search for resonator… and found a symbol similar to the Eagle symbol (note the above symbols also show in the resonator search because of keywords.):
So the confusion over the symbol in KiCad is just down to the OP not thinking to search on resonator, probably due to inexperience. Maybe “crystal” should be added to the keywords for the resonator symbols for search reasons even if it isn’t truly accurate?
A quick search of different multi-pin SMT crystals (not resonators, I know the difference) on DigiKey and I do see several (especially 4-pin) crystals where the data sheet says that the unused pins are connected to the can and should be connected to ground. So I see why there are two different symbols.
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