DP83822I: Bob smith termination

Yusuke Mukuno

Expert 7395 points

Part Number: DP83822I

Hi,

Customer is considering the method of termination.

They are refer the application note, AN-1469 PHYTER Design & Layout Guide, SNLA079D.

We are recommending the Bob smith termination 75ohm + 1000pF in this application note.

However, EVM is 75ohm + 0.01uF.

I think, capacitor value is selectable by customer. If customer change the capacitor value, How does it affect the system?

Also, Can they change the resistance value? How does it affect the system?

Also, If you have any requirement for the resistor spec like as power loss, size, etc.

Thanks

Muk

over 5 years ago

0 Aniruddha Khadye over 5 years ago

TI__Mastermind 18425 points

Hi Muk,

1000pF is the standard value for Bob Smith Termination but we have seen 10nF also work correctly. We have not tested with different resistor values so I will recommend keeping the resistors same as 75ohms.

-Regards

Aniruddha

0 Yusuke Mukuno over 5 years ago in reply to Aniruddha Khadye

TI__Expert 7395 points

Hi Aniruddha-san,

Thank you for your answer!

Customer question is ,

"How does it affect the system?"

Could you please give me your advice for it?

Thanks

Muk

0 Yusuke Mukuno over 5 years ago in reply to Yusuke Mukuno

TI__Expert 7395 points

Hi Aniruddha-san,

Could you please support for the additional question?

------------------------

"How does it affect the system?"

Could you please give me your advice for it?

------------------------

Muk

0 Nikhil Menon over 5 years ago in reply to Yusuke Mukuno

TI__Genius 11725 points

Hi Muk,

75 ohms is the standard termination for Ethernet that has been tested. We have not experimented with other values.

Thank you,

Nikhil

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DP83822I: Bob smith termination