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DS125DF111: DS125DF111 retimer configuration

OLEKSIY KASYAN
Prodigy 90 points

Part Number: DS125DF111
Other Parts Discussed in Thread: DS110DF111

Hi Support Team,

I am designing a product that requires a 10G network interface. My design includes a SoC with a 10G XFI interface, which I would like to connect to an SFP+ module. After researching online, I found that a retimer is needed between the SoC and the SFP+ module to ensure a reliable connection, resulting in the following topology:

SoC ------------- Retimer -------------SFP+ module

The DS125DF111 appears to meet my requirements for this role. However, this solution raises several questions I would like to clarify:

  1. Connection topology. Does the architecture above (SoC ------ Retimer ------ SFP+ module) seem correct? Are there any drawbacks to this approach? Is the DS125DF111 a suitable retimer for this application, or would you recommend an alternative?
  2. Retimer configuration. The XFI interface of my SoC operates at a fixed data rate of 10.3125 Gbps, which falls within the DS125DF111's supported range of 9.8–12.5 Gbps. Do the default register settings support this data rate out of the box, or is manual configuration required?
  3. Configuration tooling. I can see there is no dedicated driver for the DS125DF111. I did find a reference to the SigCon Architect 3.0.0.10 tool, which appears to support DS125DF111 configuration and monitoring. Is this tool still the recommended option? It appears to be approximately six years old — has TI released a more recent version?
  4. EEPROM programming. The DS125DF111 datasheet mentions the ability to automatically upload configuration data from an external EEPROM IC. Can SigCon Architect be used for EEPROM programming? Additionally, what I2C address should be assigned to the EEPROM IC? I was unable to find this information in the datasheet.

Thank you in advance for your assistance.

  • 0
    TI__Mastermind 41908 points

    Hi Oleksiy,

    Thanks for your detailed explanation of your application.

    OLEKSIY KASYAN said:
    Connection topology. Does the architecture above (SoC ------ Retimer ------ SFP+ module) seem correct? Are there any drawbacks to this approach? Is the DS125DF111 a suitable retimer for this application, or would you recommend an alternative?

    Yes, this is the recommended approach for DS125DF111.  In terms of alternative architectures, is there something else you had in mind?

    Using a DS125DF111 between SoC and SFP+ module requires some balance when it comes to positioning the DS125DF111 in the channel between SoC and SFP+.  The retimer relies on TX de-emphasis for any equalization after the retimer.  Depending on total channel length, you may need to consider if retimer TX de-emphasis will be sufficient to meet SFP+ eye mask and SoC eye mask.

    OLEKSIY KASYAN said:
    Retimer configuration. The XFI interface of my SoC operates at a fixed data rate of 10.3125 Gbps, which falls within the DS125DF111's supported range of 9.8–12.5 Gbps. Do the default register settings support this data rate out of the box, or is manual configuration required?

    We'll double check this, but I believe default is 10.3125 Gbps.  In case it's not 10.3125 Gbps, you could consider DS110DF111.  This is identical to DS125DF111, but has different CDR lock range.  I'm confident the default configuration on DS110DF111 supports 10.3125 Gbps.

    OLEKSIY KASYAN said:
    Configuration tooling. I can see there is no dedicated driver for the DS125DF111. I did find a reference to the SigCon Architect 3.0.0.10 tool, which appears to support DS125DF111 configuration and monitoring. Is this tool still the recommended option? It appears to be approximately six years old — has TI released a more recent version?

    Yes, this tool is still recommended.  The DS125DF111 SigCon Architect profile was developed for SigCon Architect version 2, so I would recommend using this.

    OLEKSIY KASYAN said:
    EEPROM programming. The DS125DF111 datasheet mentions the ability to automatically upload configuration data from an external EEPROM IC. Can SigCon Architect be used for EEPROM programming? Additionally, what I2C address should be assigned to the EEPROM IC? I was unable to find this information in the datasheet.

    Yes, SigCon Architect can be used to generate the EEPROM.  You can use the default EEPROM I2C 7-bit address 0x50.

    We recently discovered a discrepancy between our DS110DF111 data sheet and our EEPROM configuration application note, SNL245.  We will check if the GUI is impacted by this discrepancy and get back to you.

    More details on this:  DS110DF111: Register Detail Mismatch between DS110DF111-Datasheet and SNLA245 

    Thanks,

    Drew