DS160PT801: DS160PT801

Byungju Kim

Part Number: DS160PT801

Hi Nicholaus,

Now I'm designing PCIe Retimer Board with DS160PT801, so I need to understand REFCLK architecture of DS160PT801 for our retimer board and system.
I want to use two retimer because of long length between RC and EP.
So, I'm wondering if I need to use clock buffer IC on the RC board to share REFCLK from RC to EP.

If you look at page 33 of DS160PT801, there are REFCLK Architecture.

1. Figure 8-9.(Non-Common REFCLK Architectures Not Supported) are definite regardless of the unfinished validation?

2. If I want to use two retimer, how can I design architecture like Figure 8-8(Non-Common REFCLK Architecture)?
Should I use clock buffer IC to share RC's REFCLK to EP?

Regards,

Byungju Kim

over 1 year ago

0 Nicholaus_Malone over 1 year ago

TI__Mastermind 18340 points

Hi Byungju,

1. I realize that you were told the DS160PT801 validation was unfinished. Sorry for the confusion, but the PT801 validation is done, and the datasheet is correct that it does not support Non-Common REFCLK architectures shown in Figure 8-9. This may not be true for future revisions of the device.

2. The non-common REFCLK architecture shown in Figure 8-8 is supported! The RC clock may be shared with both retimers and root complex while the endpoint REFCLK is separate. You could even use the retimer's built-in REFCLK buffer by enabling REFCLK_OUT if desired.

Regards,

Nicholaus

0 Byungju Kim over 1 year ago in reply to Nicholaus_Malone

Prodigy 20 points

Hi Nicholaus,

Thanks for your kind reply.

About number 2, what if EP's retimer and endpoint use separated REFCLK?

I'm wondering if I design REFCLK architecture below, does retimer work?

- RC and RC's retimer use the same REFCLK, and EP and EP's retimer use separated REFCLK.

Regards,

Byungju Kim.

0 Nicholaus_Malone over 1 year ago in reply to Byungju Kim

TI__Mastermind 18340 points

Hi Byungju,

I'm not sure about the back-to-back retimer topology. I will ask internally and follow-up.

Regards,

Nicholaus

+1 Nicholaus_Malone over 1 year ago in reply to Nicholaus_Malone

TI__Mastermind 18340 points

I have sent a follow-up response by direct message. As I said there, the PT801 is designed to share a reference clock with the root complex, so it would be best for both retimers in this application to share the reference clock with the CPU.

Regards,

Nicholaus

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DS160PT801: DS160PT801