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DS80PCI402: Configuration Settings

Robert Bentley
Prodigy 20 points
Part Number: DS80PCI402

We are using the part for a design of a PCI-e Add in Card (Host Bus Adapter) for NVMe storage.

We have been told that there can be up to 10db of insertion loss to our card and possibly another 2db on the card.

On the downstream side we have a 70CM Cable to our device which has an additional 6-8" of etch. It has been characterized as having 15db loss.

I am determining the configuration settings for the redriver to provide the cleanest eye pattern at both the root and end point positions.

the 12db host path transmits into the Port B inputs and then redrives out the cable to the device.

The Device transmitter through the cable goes into the Port A receivers. and is then driven through the 12db path to the root.

can you help me determine the best configuration settings to accomplish this?

Thanks in advance.

Robert Bentley

  • 0
    TI__Mastermind 43795 points

    Hi Robert,

    If I follow the topology correctly, it sounds like the DS80PCI402 is roughly in the middle of a 27 dB PCIe channel.  Even with this level of attenuation, I recommend to start with a relatively low level of CTLE equalization to see how the system components react.  The DS80PCI402 is only one of three components that will help to equalize the total channel loss.

    Same settings in both directions.

    RATE = Float (pin configuration)

    CTLE = Level 2 - Level 4  (pin configuration EQ1 = 0 and EQ0 = R/Float/1) * Start with Level 2 *

    DEM1 = 0 and DEM0 = 1  (1000mV)

    Regards,

    Lee