DP83826E: EtherCAT Oscillator Question

Austin Trudeau

Part Number: DP83826E

Hello,

We are using two DP83826E phys, one being IN and one being OUT for EtherCAT. We are using two seperate oscillators for the X0 and XI that are the same circuits. Is there any concern with having two different clocks?

In this document it recommends having -How and Why to Use the DP83826 for EtherCAT® Applications (Rev. C)

Oscillator chosen: HLX-K-F-25.0000M-10-3050-4085

1 month ago

0 Shane Hauser 1 month ago

TI__Mastermind 35975 points

Hi Austin,

According to Beckhoff's PHY selection guide, both PHYs and the ESC need to share one clock source:

I would not recommend using two separate oscillators in your design as this would violate Beckhoffs guidelines.

Best,

Shane

0 Austin Trudeau 1 month ago in reply to Shane Hauser

Prodigy 35 points

Hello Shane,

Thank you very much for the reply. If we aren't using the distributed clock, would it still be a major concern? I believe it would be, but wanted to confirm. Thanks for the help

0 Shane Hauser 1 month ago in reply to Austin Trudeau

TI__Mastermind 35975 points

Hi Austin,

Yes it would be a concern. If you use two separate clock sources they may have frequency deviation between them. This can lead to incorrect sampling of data when no FIFO is present.

Best,

Shane

Interface

Interface forum

DP83826E: EtherCAT Oscillator Question