Part Number: DS320PR1601
Dear TI Technical Support Team,
Test setup:
- Host based on an Intel Granite Rapids processor, PCIe x16 slot
- Astera Labs PT5161LRS retimer
- Cable 500 mm Gen5 tested
- TI DS320PR1601ZDGR redriver
- Microchip PM50100PFX PCIe switch
When the host boots, the PCIe link is able to train to Gen5 with certain EQ Index settings. However, after some time the link degrades to Gen4.
The figure below shows the FOM values measured on the PM50100PFX switch while the link is operating at Gen5. For EQ Index values 3 and 5, the link falls back to Gen4 before we can complete the measurement. Gen5 link operation can also be established with EQ Index values 6 and 7. However, the measured FOM values do not differ significantly between the various EQ settings, considering the measurement variation of approximately ±5 FOM units.
When two Astera Labs PT5161LRS retimers are used in the same setup, the Gen5 link remains stable.
Could you please advise whether a stable Gen5 link is achievable in this topology (retimer + DS320PR1601ZDGR redriver)?
Do you have any recommendations for selecting or tuning the equalizer parameters for the DS320PR1601ZDGR in this application?
Thank you!
Milosh Ivkovich
