DS125BR401A : Loopback function

Hiroshi Kezuka

Other Parts Discussed in Thread: DS125BR401A, DS125BR401, DS100KR401, DS80PCI800

Hello team,

My customer is looking for 10.312Gbps quad channel repeater include loopback function.
According to DS125BR401A datasheet, there are no descripion about Loopback.

Had TI removed Loopback function from DS125BR401?

Regards,
Hirohsi Kezuka

over 9 years ago

0 Michael Lu (Santa Clara) over 9 years ago

TI__Mastermind 29655 points

Hi Kezuka-san,

Yes, the loopback function was removed from the DS125BR401A.

Thanks,

Michael

0 Hiroshi Kezuka over 9 years ago in reply to Michael Lu (Santa Clara)

TI__Intellectual 2410 points

Hi Michael-san,

Thank you for your response.

My customer need 10.3125Gbps repeater include loopback function. They don't need SAS3 support.
Is it OK to recommned DS125BR401 to customer?

Regards,
Hirosdhi Kezuka

0 Michael Lu (Santa Clara) over 9 years ago in reply to Hiroshi Kezuka

TI__Mastermind 29655 points

Hi Kezuka-san,

If the customer only requires 10.3125 Gbps support, perhaps a better part to recommend is the DS100KR401, which is a 10.3125 Gbps version of the DS80PCI800 and DS125BR401.

Regards,

Michael

0 Hiroshi Kezuka over 9 years ago in reply to Michael Lu (Santa Clara)

TI__Intellectual 2410 points

MIchael-san,

Thank you for your response. I recommended to use DS100KR401.

However customer want to know why TI removed loopback function from DS125BR401A.
They worry about DS125BR401 loopback function has some bug(?).

Would you let me know the reason why TI removed kloopback function from DS125BR401A?

Regards,
Hiroshi Kezuka

0 Michael Lu (Santa Clara) over 9 years ago in reply to Hiroshi Kezuka

TI__Mastermind 29655 points

Hi Kezuka-san,

The reason for removing the loopback function was primarily to improve the linearity of the DS125BR401A in order to support applications where link-training is required, such as SAS-3 and PCIe Gen-3. In the DS125BR401A, Channels 0-3 (B-channels) use the same channel design as the DS100KR401 and DS125BR401 in order to support long-reach applications (more EQ and de-emphasis), while Channels 4-7 (A-channels) use an advanced linear design to support link-training. Utilizing a loopback function would also result in these two different channel designs mixing. Rather than a bug, this change was done to improve the linearity of Channels 4-7.

Thanks,

Michael

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DS125BR401A : Loopback function