DP83825I: CISPR 22 Class B

Ben Campbell

Part Number: DP83825I

Tool/software:

Hello,

I see in the datasheet for DP83825, there is no mention of emissions performance. In comparison, the datasheet for DP83822 does mention it can meet CISPR 22 class B.

Should I infer that DP83825 does _not_ meet class B emissions?

Do you have any measurements of radiated and conducted emissions from these two devices for comparison please?

Thank you.

Ben

over 1 year ago

+1 Hillman Lin over 1 year ago

TI__Mastermind 25955 points

Hi Ben,

DP83825 should pass Class B performance on CISPR 22.

Please refer to the following appnote for more detail on DP83825:

https://www.ti.com/lit/ug/tidues1a/tidues1a.pdf?ts=1717698374787&ref_url=https%253A%252F%252Fwww.ti.com%252Ftool%252FTIDA-010046

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Regards,

Hillman Lin

0 Ben Campbell over 1 year ago in reply to Hillman Lin

Prodigy 80 points

Thanks Hillman for the link.

Its interesting that you shield the cable in your radiated emissions tests. Our customer's may use un-shielded cable with our product. When we test with UTP, we find there are significant emissions emanating from the cable, more than the product/PCB itself. We also find that the ethernet PHY performance is quite critical in limiting the emissions sufficiently to pass the CISPR class B. For example, imbalance in the PHY transmitter implementation causes higher emissions which are then radiated by the cable. When TI use shielded cable in their tests, we cannot really see how good the performance of the PHY is.

0 Hillman Lin over 1 year ago in reply to Ben Campbell

TI__Mastermind 25955 points

Hi Ben,

All the test we have done so far in the lab are based on the shielded cable.

Most of the customer's application nowadays uses shielded cable in their system, therefore we perform the test based on the shielded cable.

The main concern most customer looking for are the radiation due to the DUT board and the Link Partner board. Cable should not be the main factor that we normally look at when we are performing the CISPR test.

Regards,

Hillman Lin

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DP83825I: CISPR 22 Class B