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DS280DF810: Data rate and PPM tolerance setting

Toshiyuki
Mastermind 7075 points
Part Number: DS280DF810

Hi,

Our customer is considering DS280DF810 for 25.78125Gbps and 27.952Gbps data rate. We're going to set the registers as follows.Is it correct ? And, when we set 0x64=0xFF, what is the value of PPM tolerance?

the resulting register values,

Reg_0x60 = 0x40  PPM count for 25.78125Gbps

Reg_0x61 = 0x74  PPM count for 25.78125Gbps

Reg_0x62 = 0xE1  PPM count for 27.952Gbps

Reg_0x63 = 0x45  PPM count for 27.952Gbps

Reg_0x67 = 0xE0  set PPM tolerance 

Reg_0x64 = 0xFF  set PPM tolerance

Best Regards,

Toshiyuki

  • 0
    TI__Mastermind 19235 points

    Hi Toshiyuki-san,

    Settin 0x64=0xFF corresponds to +/- 1000ppm tolerance. Do note that 25.78125Gbps is a standard rate, and thus to set retimer channel to that CDR rate you simply need to set 0x2F[7:4]=0x5. The DS280DF810 does not actually support multiple VCO groups.Below are settings for channel registers 0x60 - 0x63 to manually set CDR to 27.952Gbps.

    0x60 = 0xE1, 0x61 = 0x45, 0x62 = 0xE1, 0x63 = 0x45 (since multiple groups are not supported, group 0 and 1 programmed the same)

    Cordially,

    Rodrigo Natal

    HSSC Applications Engineer