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SN65LVPE512: SN65LVPE512 Equalizer Problem

Dror Ha
Prodigy 20 points
Part Number: SN65LVPE512
Other Parts Discussed in Thread: TUSB522P

Hi,

I have integrated 2 SN65LVPE512  TI USB 3.0 re-drivers in my design as depicted in the picture below.

In order to optimize the configuration of the EQ, OS and DE I inject from BERT tester 5 Gbps, PRBS 11 signal in one side and check the eye diagram in the other side.

The amplitude of the differential signal is 1000 mVp-p.

I change the relevant EQ, OS and DE in both the re-drivers (A and B) until I receive the best eye diagram.

When I replace the HOST and inject the PRBS signal to re-driver A, so when EQ1 is changed from NC ( 0 dB) to GND ( 7 dB) I see jitter reduction in the eye as I expect but when I change EQ1 to VCC (15 dB) the eye is completely ruined and closes.

Why is that ? Why there is no additional improvement in the eye when the EQ is set to 15 dB and why the eye is ruined in this case ?

Thanks !

 

  • 0
    TI__Mastermind 23815 points

    Hi Dror,

    When using an equalizer you have to select the EQ to match the losses in the channel.

    If you have little EQ it won;t be able to recover the signal, if you have too much EQ it will over-equalize the signal and the eye will close.

    We are not recommending to use LVPE512 for new designs if possible please move to TUSB522p.

    Nir Flysher has placed the same ticket, I'm replying that ticket with the same information.

    Regard