DA9062 applying accurate clock

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J_V_Riihimaki
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DA9062 applying accurate clock

Hello,

How do I implement an external very accurate clock (< 5ppm) with DA9062?
Thank you

Best Regards,
Juha

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ED_Dialog
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Joined: 2017-09-18 11:54
Hi Juha,

Hi Juha,

There are three options for a high accuracy clock each:

  1. Use the internal free running oscillator; however this will not be as accurate as you want.  The Internal free running oscillator has a lower frequency than an externally connected crystal.
  2. Use an external 32.768Khz crystal with suitable ppm specification with appropriate tuning capacitors. The tuning capacitors are required due to the final PCB having a parasitic capacitance, so there will be need to tune the loading capacitance. We recommended placing the crystals and tuning capacitors as close to the pin as possible and then placing an earthed island of copper directly under the components on the  next layer down. We have an application note on the PCB layout, AN-PM-010, Page 12, section 4.4.2. I will post a link to the document.
  3. Use and external crystal oscillator module, the crystal module output will have to feed into the XOUT pin. This however will be the most expensive option.

I would recommend option two, based on price and space. Hope this helps.

 

PCB Layout Guidelines applcation note link:

https://www.dialog-semiconductor.com/sites/default/files/an-pm-010_pcb_layout_guidelines_1v31.pdf

Kind Regards,

Elliott Dexter