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5MHz quartz with small housing required — Parallax Forums

5MHz quartz with small housing required

ErNaErNa Posts: 1,752
edited 2009-12-16 22:50 in Propeller 1
Hi,
I wonder where to find a small 5MHz quartz, for the standard HC-form turns out to be the biggest part on the board. And, on the other hand, wouldn't it be nice to have a higher frequency, for example 10MHz, for the prop II as a standard? This will solve that problem.
Any advice on the forum?
ErNa

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Comments

  • Peter JakackiPeter Jakacki Posts: 10,193
    edited 2009-11-10 12:10
    Try CSA309 5.000MABJ-UB CITIZEN AMERICA, it's a watch style crystal, works well and doesn't take up all that room that the standard SMD xtal does.

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    *Peter*
  • AleAle Posts: 2,363
    edited 2009-11-10 12:29
    There are several alternatives, what Peter posted is probably the tiniest of the bunch!.
    Reichelt has in 5x7x1.2 mm (smd) 10 & 6 MHz oscillators, there is a smaller form factor but they do not seem to have many of those. And in HC-49 there are two besides the normal 13 mm high one, the smd version and the low-profile for through hole. The low profiles work great with the prop and are reasonably small.

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  • BradCBradC Posts: 2,601
    edited 2009-11-10 12:31
    ErNa said...
    Hi,
    I wonder where to find a small 5MHz quartz, for the standard HC-form turns out to be the biggest part on the board. And, on the other hand, wouldn't it be nice to have a higher frequency, for example 10MHz, for the prop II as a standard? This will solve that problem.

    Nothing stopping you using a 10Mhz with the prop now...

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    If you always do what you always did, you always get what you always got.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2009-11-10 16:17
    I had the same problem, went to 10 Mhz, and haven't looked back. BTW, if you're using HC49s, the through-hole parts take up less board space than the SMDs do.

    -Phil
  • Tracy AllenTracy Allen Posts: 6,666
    edited 2009-11-10 16:47
    Jauch has industrial xtals in the 7mm x 5mm x 1.8mm SMT form factor, the JXG75 series. However, 5 or 6.25mHz at 18 or 20 pF are special order.

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    Tracy Allen
    www.emesystems.com
  • Peter JakackiPeter Jakacki Posts: 10,193
    edited 2009-11-10 18:53
    Just getting back to this issue with crystals. I have always resented the HC49 smd parts because the pads took up so much room and especially if you wanted to mount the part on the same side as the Prop then it would get in the way of all the I/O pins. The TH HC49/4 always made more sense to me but I have been using the small watch style crystals now and although they are TH I find that the holes are very close together and more suitable for low-noise routing close to the Prop pins. The other benefit of this rock is that it's small and very cheap, only 36cents apiece per 100 at Digikey although I see they don't have a 5MHz version but plenty of 10MHz.

    I have use the really small and flat rectangular crystals but they are expensive and unless I am really concerned about size or stability then there is no need to use them. The ones I used where 10MHz as 5 was not available and there is no problem with 10 vs 5 I guess, just standardization.

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    *Peter*
  • ErNaErNa Posts: 1,752
    edited 2009-11-10 22:15
    Thanks all for your answers, and Peter: yes, it's just the standardization. The board should run software without modification to allow quit test.
    ErNa

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    cmapspublic3.ihmc.us:80/servlet/SBReadResourceServlet?rid=1181572927203_421963583_5511&partName=htmltext
    Hello Rest Of The World
    Hello Debris
    Install a propeller and blow them away wink.gif
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2009-11-10 23:55
    Faced with that "standarization" conundrum myself, I wrote an short object that figures out the crystal frequency (5MHz. vs. 10MHz) and sets the clock accordingly. It's posted here:

    ····http://forums.parallax.com/showthread.php?p=809968

    A program that uses clkset.spin will run with 5MHz or 10MHz crystals without changing any code or constants.

    -Phil
  • EaglemanEagleman Posts: 31
    edited 2009-12-16 22:50
    Does anyone have a part number for these tiny smt crystals to use with the prop?· Either 5Mhz or 10 Mhz.· Preferably from DigiKey or Mouser since I can include the crystal·in orders to submit for both places.
    Found it at Mouser using the P/N provided above by another poster.· Have it on order.


    Post Edited (Eagleman) : 12/17/2009 3:55:18 AM GMT
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