Signal Conditioning / redriver for SFP+ to FPGA connectoin

Niels Koll

Expert 1950 points

Other Parts Discussed in Thread: DS125BR820, DS125BR111, DS125BR401A, DS125BR401, DS100BR111

Hello,

I am designing a card with SFP+ cags that will connect to an FPGA via app. 25cm PCB and 15cm cable. Both, PCB and cable, provide 100 Ohm differntial signal routing.
Due to the expected signal loss, I want to place a redriver on my PCB.
But I do not know what kind of protocol at what speed the FPGA will run. Speed may range from 1 GBit/s up to 12.5 GBit/s. Protokol may be anything you can imagine.
Which of your redrivers would you recommend for this task?

Tanks in advance,
Niels

over 9 years ago

0 Lee Sledjeski over 9 years ago

TI__Mastermind 43795 points

Hi Niels,

Since you are supporting multiple protocols and could see any datarate from 1G to 12.5G, I would recommend using the DS125BR111. If you need more channels, there is an 8-channel version - DS125BR820.

Regards,

Lee

0 Niels Koll over 9 years ago in reply to Lee Sledjeski

Expert 1950 points

Hi Lee,

thanks for your help.

I have 4 SFPs on my PCB, so the DS125BR401 or DS125BR401A would be a "perfect fit" if I could use it.

Can you please confirm if the DS125BR401 is like 4 x DS125BR111?

I am looking forward to your answer,
Niels

0 Lee Sledjeski over 9 years ago in reply to Niels Koll

TI__Mastermind 43795 points

Hi Niels,

The DS125BR401 is essentially 4x the BR111 device. It would be a good fit.

Regards,

Lee

0 Michael Lu (Santa Clara) over 9 years ago in reply to Lee Sledjeski

TI__Mastermind 29655 points

Hi Niels,

As an addition to Lee's comments, I would like to add a clarification note:

The DS125BR401 uses the same channel design as the DS100BR111, where there are 4 EQ gain stages and programmable de-emphasis.

The A-channel (Channels 4-7) bank of the DS125BR401A use the same channel design as the DS125BR111, where there is 1 EQ gain stage and the channel is highly linear to support link-training applications. The B-channel (Channels 0-3) bank of the DS125BR401A use the same channel design as the DS100BR111. You can find more details in the DS125BR401A datasheet.

With that having been said, both the DS125BR401 and DS125BR401A are viable options for your application. I just wanted to clarify the differences in the features of both ICs.

Regards,

Michael

0 Niels Koll over 8 years ago in reply to Michael Lu (Santa Clara)

Expert 1950 points

Lee, Michael,

thank you very much for your help.

Regards, Niels

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Signal Conditioning / redriver for SFP+ to FPGA connectoin