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TLV3801: Can it be used as an LVDS Repeater

RevKy
Prodigy 40 points
Part Number: TLV3801
Other Parts Discussed in Thread: DS90LV001, DS38EP100, DS80EP100, DS25BR110, LMK04228,

I have a few LVDS signals coming off-board. Can I use this part to restore the eye diagram and provide very low jitter for the external LVDS signals coming into my PCB?

  • 0
    Guru 257000 points

    LVDS receivers work like a comparator, so it would indeed be possible to use this comparater like an LVDS buffer.

    However, 'real' LVDS receivers are optimized for LVDS signals. Consider using an LVDS buffer/redriver/repeater like the DS90LV001, or an equalizer like the DS38EP100/DS80EP100 (passive) or DS25BR110 (active).

  • 0 in reply to Clemens Ladisch
    Prodigy 40 points

    Is the DS25BR110 the lowest jitter clock repeater/driver you offer? I only need 1:1 as I am transmitting over cable.

  • 0 in reply to RevKy
    Guru 257000 points

    Yes. But higher equalizing level increase the jitter (see figures 21…24). And you would get the lowest jitter by using no buffer at all. (Does your existing LVDS receiver not work with the signal you have?)

    To remove jitter, you would need a device like the LMK04228 (and then you would have only one clock source, and generate the other clocks by dividing it down).

  • 0 in reply to Clemens Ladisch
    TI__Genius 11701 points

    RevKy,

    Thanks for reaching out. As Clemens mentioned, It is possible for TLV3801 to work for your application, which I'd like to learn more about and see if it would be beneficial for your system  I am sending you a friend request so we could discuss offline. 

  • 0 in reply to Clemens Ladisch
    Prodigy 40 points

    Okay thanks! The issue is I already have clock generation using a better PLL on a different board and I want to keep the performance of that as much as possible without significant extra cost and complexity. However, I am aware that there will be some jitter degradation as these clocks are through the cable so was looking for a relatively simple solution to buffer this clock locally without introducing huge amount of jitter. 

  • 0 in reply to RevKy
    TI__Genius 11701 points

    Hi Revky,

    For jitter of  the TLV3801, simulation results show its better than ~ 1ps; however, we did not directly test and measure jitter for this device. We do have a propagation delay skew specification (+-2.5ps) which could be helpful but it is defined by how much the low to high and high to low propagation delay varies between the OUT+ and OUT-. Not sure if this is useful for you but hopefully this gives you a few options for your system. Thanks again for your use of the forum.

  • 0 in reply to Chi Nguyen1
    Prodigy 40 points

    Okay, thanks it's something to consider. I was really looking if this (TLV3801) could be a lower jitter option than the DS25BB150 which for clock I see about the same of 1pS which is okay but for data I see it can increase to 41ps.

    I was hoping you'd have more of a view based on measurements or previous part usage.

  • 0 in reply to RevKy
    TI__Genius 11701 points

    Unfortunately we do not have jitter measurements with this part. I've sent you a friend request, could you accept so I can message you offline and share some materials that we have? In the mean time, i will close this thread. Thanks again. 

  • 0 in reply to Chi Nguyen1
    Prodigy 40 points

    Thanks, I think I have accepted already!