DS25BR100: LVDS signals not recognized by a frame grabber after DS25BR100

Kevin Lin

Part Number: DS25BR100
Other Parts Discussed in Thread: DS90CR287,

Hi There,

Our customer is using DS25BR100 as a buffer to transmit LVDS to a frame grabber, the frame grabber doesn't recognize the signals. However, if there is a 3rd party repeater, which consists of a SerDes DS90CR288 and DS90CR287, in between, the frame grabber then can recognize LVDS signals. The following is the signals captured. It's obvious that the magnitude of the signals without the repeater is higher. Is there anything we can look into?

Thank you

without the repeater from 3rd party

With the repeater in between DS25BR100 and the frame grabber

regards,

Kevin

over 8 years ago

0 Lee Sledjeski over 8 years ago

TI__Mastermind 43795 points

Hi Kevin,

What device settings are being used by the DS25BR100?

You may want to set the CTLE and DEM to 0 dB values to see if that can help.

Regards,

Lee

0 Kevin Lin over 8 years ago in reply to Lee Sledjeski

Expert 1445 points

Hi Lee,

When waveforms above were captured while EQ was pulled-low while PE was pulled-high, so Equalization Level is low while Pre-emphasis Level is medium. We have tried pulling PE low to disable Pre-emphasis, but the results are the same. Any suggestion for us to try? By the way, how do we set the CTLE and DEM to 0dB? Thank you

regards,

Kevin

0 Lee Sledjeski over 8 years ago in reply to Kevin Lin

TI__Mastermind 43795 points

Hi Kevin,

The minimum CTLE is achieved with EQ=0. When PE=0 there is 0 dB of pre-emphasis.

How does the waveform with PE=0 look? There seems to be more reflections on the redriver waveform.

Regards,

Lee

0 Kevin Lin over 8 years ago in reply to Lee Sledjeski

Expert 1445 points

Hi Lee,

Thank you for your help. The problem has been solved. It was actually the FPGA, not DS25BR100. Thank you

Regards,

Kevin

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DS25BR100: LVDS signals not recognized by a frame grabber after DS25BR100