DP83848C: FLP waveform analyze

Adrian Liu

Part Number: DP83848C
Other Parts Discussed in Thread: DP83822I

Hi Team,

The customer used our DP83848 chip, but had some problems with the FLP waveform test.

The FLP waveform of DP83848 did not see any undershoot, and the customer wanted to know if such waveform was normal. The waveform shown as below:

Because, the customer's original solution has a undershoot, as shown in the figure below.

Also, I found an Appnote at ti.com where the DP83822I was tested (e2echina.ti.com/.../dp83822i-phy-strap) and a significant undershoot can be seen.

So what is the difference between DP83848 and DP83822 please? Do we have similar test data for the DP83848 chip? Is this test result from the customer normal?

Adrian

over 1 year ago

0 David Creger over 1 year ago

TI__Genius 17810 points

Hi Adrian,

No concern here as the waveform falls within the template given by the IEEE which you have shown.

Thanks,

David

0 Adrian Liu over 1 year ago in reply to David Creger

TI__Prodigy 670 points

Hi David,

Thanks for your reply.

Yes, the waveform falls within the template.

But what the customer wants to know is, did the DP83848 originally not undershoot?

Is it a characteristic of the chip itself or might it be related to the PCB layout?

Adrian

0 David Creger over 1 year ago in reply to Adrian Liu

TI__Genius 17810 points

Hi Adrian,

I cannot say the reason for this exact waveform. It may be due to layout, probe choice, oscilloscope settings, etc. But there is no issue here since the template test is passed.

Are you seeing any other issues with the board that makes this a concern?

Thanks,

David

Interface

Interface forum

DP83848C: FLP waveform analyze