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DS25CP152: Does DS25CP152 input or output can be directly interfaced with the serdes (GTX) of Kintex-7?

Tess Chen
Intellectual 2675 points
Part Number: DS25CP152
Other Parts Discussed in Thread: DS25BR204

Hi,

A cross-point chip is required to toggle the SDI signal. We need DS25CP152 to connect FPGA Kintex-7. Does  DS25CP152 input or output can be directly interfaced with the serdes (GTX) of Kintex-7? Please give some guide on this application. Thanks.

Best Regards,

Tess Chen

  • +1
    TI__Guru* 93670 points

    Hi Tess,

    This depends on input and output common mode voltage range. DS25CP152 can be DC coupled given the following criterias:

    DS25CP152 has a wide input common mode voltage range: 0.05V to Vcc - 0.05V.

    On the other hand, output common mode voltage is: 1.05V to 1.375V and typically 1.2V.

    FPGAs normally or typically have 1.2V output common mode voltage as well. In order to not worry about common mode voltage differences, it is best to AC couple.

    Regards,, Nasser

  • 0 in reply to Nasser Mohammadi
    TI__Intellectual 2675 points

    Thanks a lot for the prompt feedback.

    We are also looking at the DS25BR204 with 2 inputs and 4outputs. The topology is shown as below. The connections are all through AC couple. Does DS25BR204 could be used in this way? Or do you have other 2 input and 4 output option to recommend? 

  • 0 in reply to Tess Chen
    TI__Guru* 93670 points

    Hi Tess,

    Your block diagram should work fine and DS25BR204 can be used in AC coupled mode as you have shown above. Please make sure you use at least 1uF AC coupling Cap values.

    Regards,, Nasser