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SN75DPHY440SS: daisy chained to compensate more losses

Zoe Ko
Expert 3830 points
Part Number: SN75DPHY440SS

Hi team,

For put a couple of MIPI retimer at both end of the cable.  DPHY440 can be daisy chained to compensate more losses.

Could you please help provide more detail and some test data to me?

Thank you!

  • 0
    TI__Expert 3655 points

    Yes, you can put two in daisy chain. For the placement and setting, please refer to the datasheet for EQ and DE settings to use. Please also pay attention to the data rate on deciding the EQ and DE. 

    Find out channel loss before and after the retimer and find out how many dB loss you need to compensate and set appropriate EQ and DE levels. 

    If you provide system topology we can help with placement review. 

  • 0 in reply to WIN Maung
    Prodigy 10 points

    Hi WIN Maung :

    Thank you for your answers, the org system block such as file_1.(MIPI 4+1 Lane_Data rate 1.3G)

    so :

    • According to your suggestion, is it like the file_2 picture?
    • Under this frame, how many dB gain between sensor and main board can we get?

    File Zip.zip

  • 0 in reply to Gufan Lai
    TI__Guru* 93670 points

    Hi Zoe,

    Thanks for sending us these two images.

    SN75DPHY440 is a linear re-driver. This means the device works like an analog  buffer with a limited gain. Given it is  a linear re-driver, this means you can put two of these in series with one another. SN75DPHY440 provides either 2.5dB or 5dB gain at 1.5Gbps Nyquist frequency. In your block diagram you are showing 1.3Gbps operation.

    1). Do you have S12 or insertion loss graph - loss versus frequency - from your image sensor to your main chip? This includes your sensor cable plus the connector and traces.

    2). SN75DPHY440 also has pre-emphasis as well - this helps to provide additional signal conditioning. Could you please let us know if your main chip has some level of equalization as well? Please let us know part number of your main chip as well.

    Regards,,nasser