ethernet compliance testing fails on our custom carrier board with the KSZ8041 PHY on our Toradex Colibri iMx7 CPU module. Layout was done in compliance with the Toradex Layout Design Guide. https://docs.toradex.com/102492-layout-design-guide.pdf
We are using LeCroy Waverunner 9404M-MS oscilloscope with the QualiPHY test kit. https://cdn.teledynelecroy.com/files/manuals/qualiphyenetmanual.pdf
The report is attached to this case. As only ANSI 184.108.40.206 - UTP differential output voltage fails, I’m asking myself where I can fix that issue. The board layout seems fine as the waveform fit perfectly into the mask. The ethernet port electronics are attaches as well. We use the Würth Elektronik 615008148521 ethernet jack.
There are no more schematics involved. Only the toradex module. Supply Voltage is 3.305V.
The differential pairs are routed closely to a reference plane and impedance controlled according to Toradex layout design guide.
What I tried so far:
LeCroyReport.pdf (713.8 KB)
I removed C31 to C34. Same error.
I separated the RX and TX termination. C22 is now only connected ro R90/R91. C30 is only connected to R97/R98.
The failure stays exactly the same.