TLV3801: Can it be used as an LVDS Repeater

RevKy

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?

8 months ago

0 Clemens Ladisch 8 months ago

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 RevKy 8 months ago 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 Clemens Ladisch 8 months ago 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 Chi Nguyen1 8 months ago 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 RevKy 8 months ago 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 Chi Nguyen1 8 months ago 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 RevKy 8 months ago 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 Chi Nguyen1 8 months ago 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 RevKy 8 months ago in reply to Chi Nguyen1

Prodigy 40 points

Thanks, I think I have accepted already!

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TLV3801: Can it be used as an LVDS Repeater