DS320PR822: Ethernet Support

Hi Mark,

What are your device requirements? I also noticed that you posted about DS280MB810 here: https://e2e.ti.com/support/interface-group/interface/f/interface-forum/1200714/ds280mb810-redriver-does-not-configure-from-eeprom/4560035?tisearch=e2e-sitesearch&keymatch=ds280mb810#4560035

If you want pin control of cross point and link training with EEPROM programming, I'd recommend DS560MB410.  If you want more advanced signal conditioning but don't actually care about link training or EEPROM, DS250DF810 would work well.

DS320PR822 is mainly target towards PCI-Express applications.

Best,

David

Hi David,

We are in process of designing out the DS280MB810 for slots of our design. We had hoped to utilize it for both Ethernet and PCIe redriver scenarios, providing our design with greater flexibility than other designs. We understood that PCIe receiver detection relies upon the presence of a far-end termination before initiating link training. And, that the DS280MB810 has internal 100ohm differential terminations on each Rx. Unfortunately PCIe requires a 50ohm single-ended termination on each leg (100ohms between the pair). Therefore, the DS280MB810 proved unable to support PCIe link training without external 50ohm terminators, and won't provide us the desired dual protocol support we seek.

Hence we are looking at the DS320PR822 redriver as possibly providing such protocol agnostic support. Yes, pin control would be very nice, EEPROM programming at initialization is definitely required, and a pin-compatible re-driver would also be of interest if available in the future (it doesn't currently appear available however).

We understand that the DS320PR822 is mainly targeted toward PCIe application, but we still desire confirmation that it works for the above Ethernet scenarios I mention. If TI doesn't wish to state such Ethernet support publicly on this forum, that's fine, but please let me know. Thank you.

Regards,

-Mark

Hi Mark,

Thanks for the additional details.  Since DS320PR822 has not been validated for Ethernet, it is difficult to know exactly how it would behave in an Ethernet system.  With that said, it is a linear redriver, similar to DS280MB810 and relies on similar technology.  Our DS320PRxxx product family are the best products that come to mind if you want to support PCIe gen4/5 and 25 GbE.  I think it is possible that the DS320PR822 would work in an Ethernet system, but since this has not been validated, I would recommend doing some simulation and testing to confirm it meets your systems requirements.

You mention that you are hoping to configure the device with EEPROM.  Would you use the same EEPROM for both PCIe and Ethernet?  One concern is that RX detect is generally set differently depending on PCIe or Ethernet.  For Ethernet, typically RX is always terminated.  For PCIe, RX detect state machine is used to determine termination.  If you are hoping to use a single EEPROM for PCIe and Ethernet, this is a potential challenge.

Thanks,

Drew