TPS23753 ground planes under ethernet tracks

Navin Narayanan

Other Parts Discussed in Thread: TPS23753A

Hi All

I'm using TPS23753AEVM-235 as a reference design for my PD.

My PD is on a 10G ethernet link. I have discrete RJ45 connector ( Wurth 634008137521) and transformer (Wurth 749050010A), not the integrated one as shown in the reference design [Wurth 7499511611A]

I have differential pairs going between the RJ45 connector and transformer, and a ground plane directly underneath the differential pairs (to get the impedance of 100ohm)

What net should I connect this ground plane to? Chassis GND, VSS or RTN (see EVM-235 for net references)

Thanks
Navin

over 9 years ago

0 Darwin Fernandez over 9 years ago

TI__Mastermind 41790 points

Hi Navin,

In the technical documents section of the TPS23753A product page there is an app that describes layout guidelines for EMI compliant PoE design. It describes that if you have a true earth connection, you can connect this ground plane you describe to it.

Regards,
Darwin

0 Navin Narayanan over 9 years ago in reply to Darwin Fernandez

Prodigy 130 points

Hi Darwin

Thanks for the answer. Looking at the app notes, would it be the BS plane that should be underneath the differential pairs between RJ45 and transformer?

Kind regards

Navin

0 Darwin Fernandez over 9 years ago in reply to Navin Narayanan

TI__Mastermind 41790 points

Hi Navin,

That is correct, if you have true earth ground, you can connect this BS plane to it.

Regards,
Darwin

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TPS23753 ground planes under ethernet tracks