DS160PR421: DS160PR421RUAR

Francis Trinh

Prodigy 30 points

Part Number: DS160PR421

Do we need external termination or AC coupling CAP for connecting data lane of DS160PR421RUAR to DS160PR421RUAR?

Thanks

Francis

over 3 years ago

0 Nicholaus_Malone over 3 years ago

TI__Mastermind 27925 points

Hi Francis,

It is best practice to include AC coupling capacitors on the Tx outputs near the connector or Rx of the receiving device. There is no external termination needed.

Regards,

Nicholaus

0 Francis Trinh over 3 years ago in reply to Nicholaus_Malone

Prodigy 30 points

Hi Nick,

This is Tx DS160PR421 to RX DS160PR421. The datasheet doesn't require AC coupling.

Thanks

Francis

0 Nicholaus_Malone over 3 years ago in reply to Francis Trinh

TI__Mastermind 27925 points

Hi Francis,

I understand. While it may not be in the datasheet, it is in the PCIe standard for Tx to have AC coupling capacitors.

If you do not want to add them, then it will probably be OK; however, it is best practice to add AC coupling caps to ensure common voltage is the same and to be compliant with the PCIe specification.

Regards,

Nicholaus

0 Francis Trinh over 3 years ago in reply to Nicholaus_Malone

Prodigy 30 points

We don't use it as PCIe. It is configured in active MUX for Video data path

0 Francis Trinh over 3 years ago in reply to Francis Trinh

Prodigy 30 points

Hi Nick,

The issue is we configure it with boot trap correctly for MUX function with PCIe disable.

We have input data, but we don't see the output.

Thanks

Francis

0 Nicholaus_Malone over 3 years ago in reply to Francis Trinh

TI__Mastermind 27925 points

Hi Francis,

I can address the question about the configuration of the MUX in your other post: (+) DS160PR421: DS160PR421RUAR - Interface forum - Interface - TI E2E support forums

I see, thank you for the clarification; however, DisplayPort specification also requires AC coupling capacitors on the Tx lines. So it is still best-practice to have AC coupling capacitors on the output of the redriver, even though it may work without it.

Regards,

Nicholaus

0 Francis Trinh over 3 years ago in reply to Nicholaus_Malone

Prodigy 30 points

Thanks Nick,

I will add AC coupling in next spin.

For now, I don't know why I don't see output.

Thanks

Francis

+1 Nicholaus_Malone over 3 years ago in reply to Francis Trinh

TI__Mastermind 27925 points

Hi Francis,

Sounds good. My first guess is that it this is related to the Rx Detection circuit, but as you said, it should be disabled. Let's talk about this issue in your other post. I will consider this one resolved.

Regards,

Nicholaus