Author Topic: EEVblog #1089 - XTAL Oscillator Teardown  (Read 1161 times)

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Offline EEVblog

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EEVblog #1089 - XTAL Oscillator Teardown
« on: May 29, 2018, 09:05:05 am »
What's inside a DIP crystal oscillator module?
A 2 minute teardown turns into 17 minutes, because, well, it's Dave. Includes a revisit of the bypass capacitor video.

 
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Offline kcozens

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Re: EEVblog #1089 - XTAL Oscillator Teardown
« Reply #1 on: May 29, 2018, 11:04:41 am »
Hm... I get first post? :)  I have used these devices for years but never stopped to think of what is inside one of these devices so this video was very interesting to watch. I did some digging around and I found a datasheet for the IC used in the small square oscillator package. The part number is SM5613N1. You can see the datasheet for it at http://www.digchip.com/datasheets/download_datasheet.php?id=877041&part-number=SM5613N1
 
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Offline SNGLinks

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Re: EEVblog #1089 - XTAL Oscillator Teardown
« Reply #2 on: May 29, 2018, 07:03:31 pm »
The reason they use a 8 MHz xtal and divide down is that a 1 MHz xtal would be too large to fit in the package.
 

Online wilfred

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Re: EEVblog #1089 - XTAL Oscillator Teardown
« Reply #3 on: May 29, 2018, 09:22:49 pm »
Why then is the thumbnail Dave shows of a 32K crystal oscillator that seems to be of the same size? And why are watch crystals so tiny?

I don't actually know why they divide down an 8MHz crystal but I'm going to guess at performance and/or production cost being more plausible than size. But I've no idea. Still an interesting video.

Why would you choose a crystal over an oscillator? Or vice-versa?
 

Offline EEVblog

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Re: EEVblog #1089 - XTAL Oscillator Teardown
« Reply #4 on: May 29, 2018, 10:02:26 pm »
Why then is the thumbnail Dave shows of a 32K crystal oscillator that seems to be of the same size? And why are watch crystals so tiny?

It's not a 32KHz crystal, it's in the MHz range.
32KHz watch crystal use a tuning fork style.

Quote
Why would you choose a crystal over an oscillator? Or vice-versa?

Oscillators will generally have a higher frequency divided down, so EMC issues, and potentially consume more power.
Oscillators are easier to implement in a system.
 

Online wilfred

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Re: EEVblog #1089 - XTAL Oscillator Teardown
« Reply #5 on: May 30, 2018, 12:45:57 am »
It's not a 32KHz crystal, it's in the MHz range.
32KHz watch crystal use a tuning fork style.

Doh!  :palm:
 

Offline mikerj

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Re: EEVblog #1089 - XTAL Oscillator Teardown
« Reply #6 on: May 30, 2018, 07:20:33 am »
I'd have thought the springs were to reduce stress on the crystal e.g. due to differential expansion over temperature.   The crystal looks a bit too light for those springs to absorb much of a shock.
 

Offline coldfiremc

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Re: EEVblog #1089 - XTAL Oscillator Teardown
« Reply #7 on: May 30, 2018, 08:34:39 am »
If this is a kind of colpitts oscillator, I really miss the other capacitor. Is inside that IC? is this another circuit?
 

Online Fungus

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Re: EEVblog #1089 - XTAL Oscillator Teardown
« Reply #8 on: May 30, 2018, 03:31:30 pm »
32KHz watch crystal use a tuning fork style.
Quote

Teardown!

Also: Accelerometer!
 

Online @rt

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Re: EEVblog #1089 - XTAL Oscillator Teardown
« Reply #9 on: May 30, 2018, 03:37:14 pm »
A vintage radio crystal I recently pulled apart used a very heavy spring
to push each electrode very tightly against the crystal wafer.
Only the disassembly releases the tension of the spring.
I can’t really tell if that’s what’s happening there.
 

Offline RoGeorge

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Re: EEVblog #1089 - XTAL Oscillator Teardown
« Reply #10 on: June 01, 2018, 06:39:23 pm »
I remember on the youtube page of this video two very, very long comments from somebody who worked in the Xtal manufacturing industry. He was talking about interesting techniques, with lots of hands on experience and historic details. It was the first comment, with a few hundreds thumbs up.

I still get notification from Youtube about replies to those long comments, but if I open the youtube page, I can not find that comment any more. Tryed another browser, no cookies , logout from youtube but with no luck finding those comments again.

Is it something wrong with the youtube site, or those comment were deleted? Can anybody else see those two long comment, please?

Offline glarsson

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Re: EEVblog #1089 - XTAL Oscillator Teardown
« Reply #11 on: June 01, 2018, 07:08:09 pm »
This film about xtal manufacturing is old but the advantage is that you can actually see the steps needed.


 

Offline thm_w

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Re: EEVblog #1089 - XTAL Oscillator Teardown
« Reply #12 on: June 02, 2018, 07:20:40 am »
I remember on the youtube page of this video two very, very long comments from somebody who worked in the Xtal manufacturing industry. He was talking about interesting techniques, with lots of hands on experience and historic details. It was the first comment, with a few hundreds thumbs up.

I still get notification from Youtube about replies to those long comments, but if I open the youtube page, I can not find that comment any more. Tryed another browser, no cookies , logout from youtube but with no luck finding those comments again.

Is it something wrong with the youtube site, or those comment were deleted? Can anybody else see those two long comment, please?

http://ytcomments.klostermann.ca/scrape
I don't see it with this tool, could be deleted or could be youtubes comment system being terrible as usual.
 
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Offline TheNewLab

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Re: EEVblog #1089 - XTAL Oscillator Teardown
« Reply #13 on: June 03, 2018, 11:47:28 am »
Has anyone tried to run the XTAL after opening it up?? or desolder that IC and use it on another circuit?  humm,  Should I try that? or remove the crystal and see it anyone can get it to work? That last one may being heading into impossible...
 


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