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DP83848-EP: Receiver specification

Etienne GOURRAUD
Prodigy 10 points
Part Number: DP83848-EP

Hello,

I am using the DP83848-EP in 100BASE-TX and I am looking for the receiver specification. I have an application with several cable configurations with different length and intermediate connector numbers between the two devices having a DP83848-EP. The datasheet (SLLSEC6E –SEPTEMBER 2012–REVISED JUNE 2019) states in §5.5.1.2.2.1 :

"The compensation or equalization must be adaptive to ensure proper conditioning of the received signal independent of the cable length." 

"The curves given in Figure 5-8 illustrate attenuation at certain frequencies for given cable lengths. This is derived from the worst case frequency vs attenuation figures as specified in the EIA/TIA Bulletin TSB-36.
These curves indicate the significant variations in signal attenuation that must be compensated for by the receive adaptive equalization circuit."

1. Does this mean that any cable of a given length that have an attenuation below or equal to the curve, will be correctly decoded? 

I have an exemple where the cable characteristics does not match the TSB-36 = EIA/TIA 568-B.2 cat5e solid, neither the IEEE clause 25 (100 Base-TX) or EN3375-11 (cable spec). 

2. Is the receiver sensible to the deviation between my cable and TSB-36?

3. Are there other parameters that shall be given to answer the questions 1 and 2?

Best Regards,

Etienne

  • 0
    TI__Expert 8640 points

    Hi Etienne,

    The cable lengths mentioned in the figure 5-7 is the maximum range tested, as long as the cable requirements meet the specs mentioned in the datasheet it should be able to correctly decode.

    If you have different cables that you want to evaluate I would recommend to use our Evaluation module for DP83848 and check if it works.
    https://www.ti.com/tool/DP83848I-POE-EK

    Regards,
    Rahul

  • 0 in reply to Rahul
    Prodigy 10 points

    Hello Rahul,

    Thank you for your answer.

    Could you be more precise about "the specs mentioned in the datasheet"? what part of the EIA/TIA 568-B.2 shall my cable fullfill? 

    I am surprised that only the attenuation criteria is quoted in the datasheet.

    I cannot test my different cables with your evaluation board as I'm not able to reproduce every conditions. Could I simulate my cables with a generator? What would be the required sample rate and characteristics?

    Best Regards,

    Etienne

  • 0 in reply to Etienne GOURRAUD
    TI__Expert 8640 points

    Etienne,

    Etienne GOURRAUD said:
    Could you be more precise about "the specs mentioned in the datasheet"?

    TSB-36

    Etienne GOURRAUD said:
    I cannot test my different cables with your evaluation board as I'm not able to reproduce every conditions. Could I simulate my cables with a generator? What would be the required sample rate and characteristics?

    We do not have much data available on this part other than the datasheet. Apologies for the inconvenience.

    Regards,

    Rahul