TDP142: AC coupling of AUX pin

R.Fukunaga

Expert 2525 points

Part Number: TDP142

Tool/software:

Hi all,

When connecting to the DisplayPort Sink, The AUX pin has AC coupling and pull-up and pulldown.

However, when connecting to the DisplayPort Receptacle, it is not connected with AC coupling but directly connected.

Is this a typo?

Best Regards,

Ryusuke

10 months ago

0 David (ASIC) Liu 10 months ago

TI__Guru**** 177926 points

Ryusuke-san

This is not a typo. The DP source that is connected to the DP receptacle has the AC coupling capacitor and 100k pulldown on AUXP and 100k pullup on AUXN.

Thanks

David

0 R.Fukunaga 10 months ago in reply to David (ASIC) Liu

Expert 2525 points

Hi David,

I understand AC coupling is not required when using DP Sink.
Is my understanding correct?

Should I not attach AC coupling cap?
If not, why?

Best Regards,

Ryusuke

+1 David (ASIC) Liu 10 months ago in reply to R.Fukunaga

TI__Guru**** 177926 points

Ryusuke-san

If you have the TDP142 designed on the same side as a DP source, you would follow the below implementation.

If you have the TDP142 designed on the same side as a DP sink, you would follow the below implementation.

If TDP142 is between the DP source and DP sink, then there is no need for AC coupling capacitors since the capacitors are already present in the source and the sink as shown below.

Thanks

David

0 R.Fukunaga 10 months ago in reply to David (ASIC) Liu

Expert 2525 points

Hi David,

Thank you for your reply and clear explanation.

I understood.

Best Regards,

Ryusuke

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TDP142: AC coupling of AUX pin