SMD Crystal or equivalent for MCU

[FrankT]

I'm looking for a small SMD crystal, or equivalent, for my micro-controller circuit. 

I have always used through hole crystals, either the HC-49 package or cylinder type, but they always look monstrous compared to the rest of the circuit.

This will be for an ATTINY45 with an 8MHz crystal.  I need accurate timing and repeatability.

Any recommendations for hand SMD solderable crystal packages?  Or are resonator circuits an option (software guy here, I don't really know the differences)

Thanks,
Frank

[Araho]

Have you tried looking through Digikey? They have an excellent system for finding parts like this, where you know both the name of the part and the value.

Here is a link to all SMD crystals with a frequency of 8MHz. You can further sort by size, load capacitance, stability and a whole host of other criteria.

Standard SMD crystals with a formfactor like this can be hand-soldered easily.

[FrankT]

Thanks for the reply. 

That's the type that I always seem to find.  SMD, yes.  But they are the same physical size as the through hole equivalent.  Even the lower profile ones, are still 10x3mm, twice the size of the MCU.

[sleemanj]

How accurate do you need?

http://jorisvr.nl/arduino_frequency.html

Ceramic resonators can come in very very tiny packages, at the expense of less accuracy and stability, 0.1% to like 0.5%.

Difference is accuracy/stability, with resonators much better than the internal RC oscillator, and crystals much better than resonators


I have a few of these 3.2mm x 1.3mm ceramic resonators on my desk at the moment waiting for me to use them, very very tiny.

[FreddyVictor]

how about these - size is 5mm x 3.2mm
you can make the land pads a little bigger if you don't have a re-flow station

[FrankT]

how about these - size is 5mm x 3.2mm
you can make the land pads a little bigger if you don't have a re-flow station

Yes, that's what I'm looking for.  I don't know why I couldn't find them.  On the digikey website, I ended up with on 17 items, and they were the old clunk HC49 style case.

I will also have a look the ceramic resonators.  My project is to drive RC servos and control the position based on the current draw, so I don't think it needs to be accurate, just not drift over time.

[sleemanj]

I will also have a look the ceramic resonators.  My project is to drive RC servos and control the position based on the current draw, so I don't think it needs to be accurate, just not drift over time.

If a resonator works (and I'd think it probably would), then you get the advantage of not needing the two capacitors a crystal needs which can save quite a bit of space too.

[Araho]

Sorting by size on my previously linked list, after checking "In stock", I found this: http://www.digikey.no/product-detail/en/NX3225GD-8MHZ-STD-CRA-3/644-1178-1-ND/3125567

3.2mm by 2.5mm seems small enough, right?

A little bit further down I also found the same as mentioned above by Freddy. It pays off to learn to use the parameterized search!