SN75LVPE5412: EQ setting

Hi Jeff,

We analyze PCIe applications in terms of insertion loss instead of PCB trace lengths because redriver performance and PCIe specifications are calculated in terms of dB. I don't know the insertion loss per inch for the material the customer is using. You can ask their SI engineers to calculate the total loss in the PCIe link before and after the redriver, including the CPU package loss and endpoint loss if they know, and usually then we can estimate what redriver settings would be a good starting point for tuning.

Best,

Evan Su

Hi Jeff,

Thanks for the update. For the DS320PR810 link we have 12.8 dB + 8.2 dB = 21 dB shown here. If I roughly assume 8 dB for the CPU package loss and 9 dB for the endpoint that will go into the slot then the total link loss is about 38 dB, which is only slightly above the PCIe Gen 5 loss budget. Therefore I would suggest EQ 0 as a starting point, or if the DS320PR810 would be run in EEPROM/I2C mode they can try the basic EQ Default too.

For the SN75LVPE5412/421 link we have about 10.5 dB + 10.0 dB = 20.5 dB shown here, and again the total link loss is only slightly above the PCIe Gen 5 loss budget. Typically the SN75LVPE5412/421 redrivers are run in pin mode, so I would suggest EQ 0 as a starting point. But again they can try EQ Default if they are using a mode with I2C.

Best,

Evan Su