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SN65LVDS94 (LVDS input signal spec)

Ho Cheol Song
Prodigy 130 points
Other Parts Discussed in Thread: SN65LVDS94

Dear Team,

I am a FAE in Serial Korea, in charge of All analog parts. ^^

I have one question about LVDS signal specification of SN65LVDS94(LVDS Receiver).

Customer : Digen (Application : AVN)

Question>

-       Currently, as a result of measurement, Vp-p at CLK+ line is about 130mV. (Refer to the below image for this wave pattern.)

-       Is it right? Is there any problem to receive the LVDS data through SN65LVDS94? (Customer wants to know what the minimum Vp-p of LVDS signal is.)

        

If you have any concern, please let me know it.

Thanks&Regards

  • 0
    TI__Mastermind 20985 points

    Ho Cheol Song, are these schematics confidential?  Are you sure it is ok to post them on the entire Internet?

    Is the signal only 450Hz?  This isn't right.  The SN65LVDS94 supports 20MHz to 68MHz.

    TIA/EIA-644-A LVDS typically has a voltage swing from 1.025V to 1.375V, where VOD swings from -350mV to 350mV.  The SN65LVDS94 has a "VIT" spec of 100mV, so it can detect a VOD of >100mV.

    Best regards,
    RE

  • 0 in reply to RE
    Prodigy 130 points

    Thank you for your quick response.

    I captured only the section of SN65LVDS94, and it's also confirmed from customer. Anyway I revised previous post.

    In your comment, I don't know what VOD is... Does It mean Vp-p of LVDS specification? (I don't have lots of information about LVDS...^^)

    Could you kindly explain it with the below diagram?

     

    Seperately, Could you have EMI solution for LVDS signal? If you have, please let me know it.

    Thanks.

  • 0 in reply to Ho Cheol Song
    TI__Guru* 76130 points

    Hello,

    Please see the picture below, it is an example of the different parameters that the waveform on your scope capture show.

    The minimum absolute value of VID that the SN65LVDS94 requires is 100mV, so if the scope capture that you are attaching is of a single ended clock input to the LVDS94, then you should have a VID swinging from -130mV to 130mV which meets the minimum requirement.

    However, as Ross said, the minimum input frequency for the LVDS94 is 20MHz.

    Regards.