D0WDQ6 External Crystal Selection

louislewis2
Posts: 4
Joined: Wed Dec 04, 2019 6:28 pm

D0WDQ6 External Crystal Selection

Postby louislewis2 » Tue Sep 08, 2020 9:00 pm

Hi,

I am hoping someone will have some insight.
I am currently building out a board using the D0WDQ6. Following the reference design, from the
hardware design guidelines and the reference design for the Wrover-b things have gone pretty smooth.
Then I hit the external crystal.

I use Easy Eda, and parts from Lcsc.
I can only find 2 crystals which match the 40Mhz, 10ppm values.
The footprints do not match the schematic. I am not an electronic expert, which most likely prevents
me from seeing the possible obvious.

Most of the footprints have 4 pins, which is good so far, but the reference design shows 2 going to ground,
and this is where I fall off.

YSO110TR:
1: Enable / Disable
2: Ground
3: Vdd
4: Out

SG– 8101s:
1: Output Enable
2: Ground
3: Out
4: Vcc

Reference Design
1: XIn
2: Ground
3: XOut
4: Ground

Sorry if this is a silly question, I did try search the forum for an answer on this.

Also is there a known preferred crystal?
Has someone else possibly used a crystal available from Lcsc which they can recommend?

The next issue is that using Jlc PCB for population, they do not populate the above 2 components.
While I do have a reflow over, it would be great if I could use a component that they do support.
I have found this one

Yangxing Tech O705040MEDA4SC
Lcsc Number: C24796

This unit has an accuracy of 20ppm, would this dramatically effect the operation of the unit?

Thanks

ESP_Sprite
Posts: 9766
Joined: Thu Nov 26, 2015 4:08 am

Re: D0WDQ6 External Crystal Selection

Postby ESP_Sprite » Wed Sep 09, 2020 7:28 pm

I don't think those are crystals, rather crystal *oscillators*. Different thing. Furthermore, a higher PPM than advised in the docs will likely affect WiFi/BT operation, though I can't say by how much.

louislewis2
Posts: 4
Joined: Wed Dec 04, 2019 6:28 pm

Re: D0WDQ6 External Crystal Selection

Postby louislewis2 » Thu Sep 10, 2020 6:59 pm

Hi,
Your reply, certainly led me down the right path.
I found the items I was looking for. Turns out they were hiding under Crystal Resonators.

Thank you for your time, much appreciated.

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