• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 33 subscribers
  • Views 447 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

DS125BR820: Insertion loss

DS125BR820: DS125BR820 for Series application

Hugo Liu
Genius 5095 points
Part Number: DS125BR820
Other Parts Discussed in Thread: DS125BR800A

Hi Sir,

Our customer want to use the DS125BR820 on Storage application, But the trace is very long,

we can repeater connect repeater for Series application? or do you have other device can be share for me?

Hugo

  • 0
    TI__Mastermind 43795 points

    Hi Hugo,

    Using the DS125BR820 for SAS-3 storage applications with a total channel loss over 35dB is high risk.  The SAS-3 system components are designed for 24 dB of compensation and the DS125BR820 adds another 10dB of compensation. 

    We do not recommend using multiple DS125BR820 devices in series to extand the capability to longer traces.

    Do you know the maximum loss of this channel?

    Is this a SAS-3 application?

    Thanks and Regards,

    Lee

  • 0 in reply to Lee Sledjeski
    Genius 5095 points

    Hi Sir,

    Our customer is use on PCIe application, as below is Total loss topology.

    Is this not recommend using multiple DS125BR820 devices?

    Hugo

  • 0 in reply to Hugo Liu
    TI__Mastermind 43795 points

    Hi Hugo,

    This is a long and complicated channel.  I would not usually recommend repeaters for this application.  If I needed to try to make it work I would recommend using a single DS125BR800A in each path. 

    The most difficult issue to solve is the upstream path from the Add-in-Card to the CPU.  The best location for the redriver in this path is on the motherboard and it is not typical to have room for the redriver in this location.  For the downstream path the redriver would need to be on the riser card. 

    Regards,

    Lee