I'm trying to locate the 32.768K crystal (Y2) on the 52840 board:
https://i.imgur.com/Ogm6SlA.jpg
That one says "SGM49A" on it, and the nRF5232 board says "SGL47A".
This part is labelled in the Eagle pcb files as device "XTAL-3.2X1.5 (XTAL)" and package "XTAL3215", but those don't seem to translate to a MPN# that I can find. Is there a pF and kOhms rating on the crystal I could use to match up with one on digikey or aliexpress?
There are quite a lot of these NX3215 crystals on digikey, with varying values, and I don't really want to take a gamble that I'll pick the right one.
https://www.digikey.com/products/en?keywords=NX3215
I also found this page which is the manufacturer of the crystal that's on Nordic's Dev board, but it doesn't (at least visually) look like the same one:
https://www.golledge.com/news/mp06003-m ... -nrf52840/
Does anyone happen to know, or know of one that did work?
Thanks!
Which 32.768KHz crystal is used on the NRF52 feather boards?
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Please be positive and constructive with your questions and comments.
- dstein
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- Franklin97355
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- Joined: Mon Apr 21, 2008 2:33 pm
- dstein
- Posts: 12
- Joined: Mon Apr 24, 2017 12:35 pm
Re: Which 32.768KHz crystal is used on the NRF52 feather boa
Thanks, yeah those Kyrocera crystals look just like the ones on the board.
Do you know what effect the pF rating would have?
For example, there are also 7pF and 9pF versions of the Kyrocera crystals:
https://www.mouser.com/ProductDetail/Ky ... 4WTFeEs%3D
https://www.mouser.com/ProductDetail/Ky ... MgxElEg%3D
I don't know what the recommended value is, but the Nordic DK board uses one with 8pF.
Do you know what effect the pF rating would have?
For example, there are also 7pF and 9pF versions of the Kyrocera crystals:
https://www.mouser.com/ProductDetail/Ky ... 4WTFeEs%3D
https://www.mouser.com/ProductDetail/Ky ... MgxElEg%3D
I don't know what the recommended value is, but the Nordic DK board uses one with 8pF.
- Franklin97355
- Posts: 23940
- Joined: Mon Apr 21, 2008 2:33 pm
Re: Which 32.768KHz crystal is used on the NRF52 feather boa
It might be specified in the crystal's datasheet.
- dstein
- Posts: 12
- Joined: Mon Apr 24, 2017 12:35 pm
Re: Which 32.768KHz crystal is used on the NRF52 feather boa
You're right, there was a spec document about the recommended crystal on the Raytac website:
https://www.raytac.com/document/index.php?index_m_id=12 (the first download contains the crystal spec)
Looks like the recommended crystal is an Epson Toyocom, production code FC-135 with 9pF:
https://i.imgur.com/wnEhixs.png
I don't know what it means by "external capacitor=12pf". The Adafruit board connects two 22pF capacitors to each end of the crystal.
I found a part that looks like a match on Digikey:
https://www.digikey.ca/product-detail/e ... ND/6132704
https://www.raytac.com/document/index.php?index_m_id=12 (the first download contains the crystal spec)
Looks like the recommended crystal is an Epson Toyocom, production code FC-135 with 9pF:
https://i.imgur.com/wnEhixs.png
I don't know what it means by "external capacitor=12pf". The Adafruit board connects two 22pF capacitors to each end of the crystal.
I found a part that looks like a match on Digikey:
https://www.digikey.ca/product-detail/e ... ND/6132704
Please be positive and constructive with your questions and comments.