• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 33 subscribers
  • Views 750 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

TDP142: Re-driver at RX side adds jitter in 3m cable 8.1Gbps scenario

TDP142: Phase Response of CTLE?

Zhiwei Zhang
Prodigy 30 points
Part Number: TDP142
Other Parts Discussed in Thread: DS100MB203

Hi, 

After trying DP cable as discussed in https://e2e.ti.com/support/interface-group/interface/f/interface-forum/1169055/tdp142-re-driver-at-rx-side-adds-jitter-in-3m-cable-8-1gbps-scenario, I noticed that one Re-driver is not able to fully compensate 8.1Gbps 3m DP cable loss. So I add another TDP142 to further boost high-frequency gain. But dispersion is observed after the second re-driver.

Increase EQ improve eye height indeed but reduce eye width, due to deterministic jitter. I think it's because non-linear phase response of CTLE. The more re-drivers cascaded, the more non-linear.

1) Is there any phase response info on TDP142? I'd like some input to further analyze this issue

2) Based on non-linear hypothesis, does it make more sense, if I use EQ with higher boost, instead of two CTLE cascaded, e.g. DS100MB203 (though not designed for DP). As one CTLE introduce less phase lagging compared to two cascaded.

3) If yes to 2, do we have phase response info on DS100MB203?

Thanks!

Regards,

Zhiwei