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SN75LVDS82: SN75LVDS82 abnormal while pot display...

Peter Tseng
Mastermind 6260 points
Part Number: SN75LVDS82
Other Parts Discussed in Thread: SN75LVDS83B

Hi Team,

My customer use SN75LVDS82 to interface with i.MX8 and has while noise abnormal display issue.

Their original design is:

GPU(AMD LX800)(TTL-DRGB-24bit) -> TI SN75LVDS83B -> [LVDS] -> TI SN75LVDS82 -> TTL TFT panel and work well.

However, due to AMD LX800 will EOL and they changed to i.MX8 which supports LVDS output.

GPU(i.MX8)(LVDS) -> TI SN75LVDS82 -> TTL TFT panel 

There is an issue with this connection now.

They found the LVDS signal level are different.

i.MX8:

SN75LVDS82:

May this be the root cause?

If yes, what other solution will you suggest to interface with i.MX8?

Thanks.

  • 0
    TI__Mastermind 18046 points

    Hi Peter, 

    This could be part of the issue. Is the customer seeing this abnormal display issue on multiple systems with the new design? And does the abnormal display happen right after power up or over time?

    Also is there any reason the customer is dropping the SN75LVDS83B Transmitter? Can you share the application requirements of the customer design (such as pclk, resolution, pin count etc...)

    Best,

    Shu

  • 0
    Guru 317680 points

    The VIL/VIH specifications do not describe the LVDS inputs. The i.mx8 and SN75LVDS82 are compatible with each other; this has been discussed in this thread: SN75LVDS82: LVDS.

    It also says:

    White dots are sometimes a byproduct of something related to the power supplies (or noise on the power supplies). Please check that the power supplies are functioning correctly by probing the power rails.