DP83867IR: Failed distortion at compliance test

Hi Mochizuki,

1. Can you please share register config script used for this test, and layout files?

2. Please refer to Table 9-1 for pulse transformer requirement:

Reference transformer is HX5008NL, this follows above spec and is used on DP83867EVM:

https://www.digikey.com/en/products/detail/pulse-electronics/HX5008NL/1036960

Thank you,

Evan

Hi Evan, 

Thank you for your information.

Would you please review attached register setting. 

And PCB layout is DP83867IRPAP-EVM as it is.

Regards,

Mochizuki

DP83867_Register.xlsx

Hi Mochizuki,

Thanks for confirming. Due to U.S. holiday, please expect feedback on register log by 5/29 latest.

Regards,

Evan

Hi Mochizuki,

The PHY config in register log looks good to me for transmitter distortion test.

For the schematic, please help confirm the following:

- What is the spacing between MDI traces?

- Which CMC is being used, and does it follow the magnetics requirements in datasheet?

- Are the center taps shorted for the CMC?

Thank you,

Evan

Hello Even,

Thank you for your review of register setting.

About PCB layout, it is TI EVM. https://www.ti.com/lit/ug/snlu176/snlu176.pdf?

Please find out those dimensions.

Regards,

Mochizuki

Hi Mochizuki,

My mistake, I misread initial post. I will discuss with team and share suggestions with you tomorrow.

Thank you,

Evan

Hi Mochizuki,

Gigabit compliance tests have historically been challenging to pass. To improve the margin for this test, I recommend following the schematic and layout checklists with DP83867:

https://www.ti.com/lit/zip/slvrbn1

https://www.ti.com/lit/zip/snlr048

Thank you,

Evan