TPS23753: MDI interface maximum trace length

Parag Bisen

Part Number: TPS23753

Hello Team,

We are using TPS23753PW in our design for the POE 802.3af .
I have one concern , we are planning to place magnetics in one board and TPS23753PW in the different board which is main board and will connect the both board with FPC connector and cable . The Overall distance for the MDI signals(Tx_P, TX_N, RX_P, RX_N) from the magnetics to the Phy IC will be 200mm to 250mm . and also signal will travel through the FPC cables . Does this much distance between the magnetics and PHY IC are allowable ? will it create any issue ? will there be any signal distortion or the degradation?

11 months ago

0 Diang Xing 11 months ago

TI__Mastermind 21941 points

Hi Parag,

Thanks for reaching out.

Sorry that I do not have a clear answer for your question. There could be potential distortion issue when the data line is close to EMI sources. Shield or twisted wires could alleviate the issue, so signal distortion in a long Ethernet wire is not significant normally. For board layout point of view, try to make the data line short and far away from high current traces, switching nodes, or switching inductor / transformer.

Best regards,

Diang

0 Parag Bisen 11 months ago in reply to Diang Xing

Prodigy 45 points

Hello Diang,
Thank you for the response
it means i cannot place magnetics in one board and ethernet phy on the another ,as it will increase the distance of the MDI signals ,right ?