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DS125BR401A: Application questions

Penn Zhang
Intellectual 1180 points
Part Number: DS125BR401A

Hello,

Could you help me confirm on the below questions, thanks in advance.

1. We recommend connect the bigger loss at the channel B side as the B side have the 24dB CTLE, am I right?

2. I have checked the positive and negative trace for one lane looks the same, may we swap the outside connection for easy layout?  Like I connect outside Negative trace to device positive pin, connect positive trace to device negative pin? is this acceptable?

Thanks.

  • 0
    TI__Guru* 93630 points

    Hi Penn,

    1). Yes your understanding is correct. B side can compensate for higher loss - up to 24dB. Since B side can tolerate more losses, this side is put on the receiving side - where there are more signal energy loss. On the other hand, A side can tolerate close to 10dB. Normally A side is used on the TX side and there should be 4-5dB loss between ASIC/FPGA TX and A side input. This allows signal training sequences from FPGA/ASIC to pass through the A side seamlessly. 

    2). Yes you can swap P and N on input and output. If you do this just on one side, it is like negating the signal. But if you do this on both input and output then it is like negating twice and thus the result is positive(no change).

    Regards,, Nasser