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DP83640: PHY signal issue (RD+/-, TX+/-) with Ethernet (RJ45)

Myung Han
Prodigy 40 points
Part Number: DP83640

I had an issue with intermittent communication (loss communication) between our instrument and an workstation. The main issue was that signal waveform is not good showing with eye pattern. It seems to get a noise added on it. So with guidance by TI support, we did layout PCB again. But it is the same waveform before doing a layout of it.

Here are the signal capture by Oscilloscope. This signals are between Phyter device and RJ45 (Ethernet Connector) and it is on RMII Master Mode with 100Mbps.

This is the waveform at PHY side (RD+/-, pin14/pin13). This RD+/- signal looks O.K.

But this is the waveform for TD +/- (pin17/pin16).

But is this corrected the signal waveform of TD+/- for the DP83640 device?

It seems the signal still have an noise on it. And so I read one of Ethernet forums as similar symptom for the signal waveforms with DP83640 (Phyter chip).

Here is the link as ;

e2e.ti.com/.../316528

Could you give your advice for this issue?

Regards

Myung