DS50PCI402: DS50PCI402

Greetings,

1). I reviewed the older E2E case you had noted related to the AC coupling cap. I am assuming the issue you noted here is still related to the AC coupling Cap location. Or the scenario you mentioned about AC coupling Cap still applies. Could you please confirm?

2). You noted "the link up issue was improved". Does it mean there is still some cases where link up is not successful? Please confirm.

3). In your application, what is the data pattern coding being used? 

4). Link up issue: Is this PCIe or other standard? Any idea as to where in the link up is the cause of the failure to link up?

It would be helpful to understand these questions so we can get a better understanding of the root cause.

Regards,, Nasser 

Hi Nasser ,

Thank you for your reply.

>1). I reviewed the older E2E case you had noted related to the AC coupling cap. I am assuming the issue you noted here is still related to the >AC coupling Cap location. Or the scenario you mentioned about AC coupling Cap still applies. Could you please confirm?

>2). You noted "the link up issue was improved". Does it mean there is still some cases where link up is not successful? Please confirm.

⇒I remove AC coupling cap of RX side, this means only AC coupling cap of TX side based on older E2E.

    However  link up is not successful sometimes.

>3). In your application, what is the data pattern coding being used? 

>4). Link up issue: Is this PCIe or other standard? Any idea as to where in the link up is the cause of the failure to link up?

⇒PCIe Gen2 , so 8B/10B encoding.

Again, Is there specification of minimum length(trace) to use EQ of DS50PCI402?

If the length(trace) is shorter than 8 inch(FR4), is it not effective for using EQ?

Best Regards,

ttd

Hi Nasser,

>Some equalizers may have residual gain in order of 2-3dB even when the device is optioned for bypass mode.

According to the datasheet, bypass mode shows 0dB. 

Does DS50PCI402  residual gain in order of 2-3dB? If yes, is it cause link issue like eye close?

I recognize that"Bypass mode" = "Pattern only (no device)"

But is it not correct?
It is necessary to find out the cause of link issue with Bypass mode and OK  case is  only removing device(no device).

PS. this issue seems to cause between some different lot (some lot OK , some lot NG).

Best Regards,

ttd