DP83822I: DP83822I: Eye waveform testing fail at 100M Base-T

Hi Liang,

Can you please share the schematic of your design?

Please share the eye mask also for reference.

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Regards,
Gokul.

ECG-RBIAS=4.87K_Rout=3.3ohm_RPU=62ohm_Fail2.PDFDP83822I_PHY_SCH.pdf

Hi Gokul, 

Attached the files for reference

Hi Liang,

Can you please let me know the following?

1. What are the values of the resistors R321,R322?
2. I see that there are 2.2ohm and 5.1 ohm resistors on MDI path? Why are these mounted?
3. Can you please try with C49=10nF instead of 1nF?
4. Can you please use C42,C44 = 1uF+0.1uF instead of 0.1uF alone?
5. Can you please try and check with removal of all ESD diodes?

--
Regards,
Gokul.

Hi Liang,

Did you manage to do these experiments?

--
Regards,
Gokul.

1. R321,R322 are 0ohm

2. 2.2ohm and 5.1ohm for lightning protection

3. ineffective

4.  C42,C44 = 1uF+0.1uF,  is ineffective

5. ESD diodes must not be removed，for ESD and lightning protection。

Is there register for matching， that we can adjust it through software codes ?

Hi Liang,

Let me have a review with our team and get back to you.

--
Regards,
Gokul.

Hi Liang,

Happy New Year!! Sorry for the delay in my response.

We couldn't find any registers to correct this as we don't understand the reasons for failure. Once we understand the rootcause, we can check again if we can do something with registers.

For experiments only, can you please remove series resistances of 2.2ohm, 5.1ohm and remove the ESD diodes and check the mask? We want to look at the performance without these components to understand why there are failures.

--
Regards,
Gokul.