DP83TG720R-Q1: MDI Network Issues with worse than 1% tolerance

Hi Sreenivasa,

We do not have a schematic right now but one of my accounts is creating one and wanted to understand how crucial the recommendations in the datasheet are.

If you say it is okay to use a 4700pF 50V 10% tolerance cap then we will continue with that. Once a schematic is complete I will send it internally.

Regards,

Kevin

Hello Kevin

Thank you for the reply.

For doing the functional testing, this configuration is ok.

Regards, 

Sreenivasa

Hello Kevin

If you do not have additional questions, please click the resolved button to close the thread.

Regards,

Sreenivasa

actually it sounds like they plan on doing some compliance testing. Do you know what compliance issues this may cause? Is it primarily with EMI/EMC?

Hello Kevin

Thank you for the reply and that is correct. 

Regards,

Sreenivasa

Hello sorry to open this again!

I realized I was talking about the wrong capacitors! They wanted to understand how crucial the DC blocking caps being 1% 0.1uF are. In the datasheet Table 9-1 we recommend 1% tolerance but in the EVM we use 10% caps.

What issues might come up if we use 0.1uF, 50V, 10% caps for the DC blocking caps? Will it just be EMI related or will there be no issue?

Regards,

Kevin

Hello Kevin

Thank you for the query.

The 1% tolerance is for the resistors and 10 % tolerance as used in the EVM should be fine.

The effect may be seen while performing the Ethernet compliance tests.

Regards,

Sreenivasa