DS125BR820 simulation issue (urgent)

Patrick Chen

Other Parts Discussed in Thread: DS125DF1610, DS125BR820, DS125DF410

Hello,

Below is customer topology and the simulation results are very poor.

1. How to improve simulation results by below topology. Place DS125BR820 to other position of PCB? Or could use DS125DF1610/DS125DF410 to improve? Has any comments for this issue?

2. If one DS125BR820 could't get better performance, do we place 2nd DS125BR820 on the front I/O board to enhance performance? Is the application recommend to this topology ?

Patrick

over 9 years ago

0 Lee Sledjeski over 9 years ago

TI__Mastermind 43795 points

Hi Patrick,

What is the overall channel loss for this system from SAS expander to HBA?

Placing a 2nd DS125BR820 on the "I/O Board" will help a little. In practice the 2nd BR820 will only improve the overall reach by a few dB @ 6 GHz. The reason for this is that very high loss channels will be impacted by crosstalk/noise more than a short, less lossy channel.

SAS backchannel training and OOB signaling are not compatible with our DS125DF410 / DS125DF1610 retimer technology.

Regards,

Lee

0 Patrick Chen over 9 years ago in reply to Lee Sledjeski

Mastermind 8875 points

Thanks. Lee.

Do you have other suggestion to improve the performance? Thank you.

Patrick

0 Lee Sledjeski over 9 years ago in reply to Patrick Chen

TI__Mastermind 43795 points

Hi Patrick,

Please ask the customer how much attenuation they expect in each part of the system channel.

Please ask them what models and model settings they are using for the SAS-3 Tx and Rx.

Thanks and Regards,

Lee

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DS125BR820 simulation issue (urgent)