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LMH0397: Condition that video data cannot be detected

Sadanori Kato
Guru 36540 points
Part Number: LMH0397
Other Parts Discussed in Thread: SIGCONARCHITECT,

Hi,

MODE_SEL is pulled down to VSS with 1kΩ resistor, ENABLE is pulled up to VIN(2.5V) with 1kΩ resistor and SCL and SDA are pulled up to 3.3V with 4.7kΩ resistors.
So, is there any condition that video data cannot be detected and video isn't output when the above input terminals are fixed?
If yes, please give me the details of the conditions.

Best regards,
Kato

  • 0
    TI__Guru* 93670 points

    Hi Sato-San,

    I believe connections you have should enable the device to operate but there are some comment which may help to debug this problem.

    1). I am assuming EQ/CD_SEL pin is pulled low or it is floating(EQ mode). 

    2). Can you read current consumption by the device? If there is no signal device would draw less than 20mA.

    3). Is it possible to use SigconArchitect GUI to check if carrier is detected?

    4). I am assuming you are using a valid video. If you loop back the video back to the video analyzer you are observing a 3G or lower video running error free.

    5). What cable length are we using? Can we try 30 or 50m cable length?

    6). Do you see this at every video rate?

    Regards,, Nasser

  • 0 in reply to Nasser Mohammadi
    Guru 36540 points

    Hi Nasser-san,

    Thank you for your prompt reply.

    Please see the following comments.

    1). EQ/CD_SEL is pulled down to VSS with 1kΩ resistor. As you mentioned, EQ mode is used.

    2). I will confirm the current consumption with our customer.

    3). Which "SigCon Architect" should be downloaded for LMH0397 prototype board? Is "SigCon Architect Installer wRTE" correct? Additionally, please tell me how to check in detail whether carrier is detected with "SigCon Architect".

    4). Please let us know if you have a recommended video analyzer. Additionally, please tell me the measuring equipment to monitor OUT0± which is used as host-side loopback output for monitoring purposes.

    5). I will confirm the current consumption with our customer.

    6). I will confirm the current consumption with our customer.


    By the way, have you ever experienced that video signal wasn't output normally when the noise was input to the I2C bus?

    Best regards,
    Kato

  • 0 in reply to Sadanori Kato
    TI__Guru* 93670 points

    Hi Kato-San,

    In another E2E response i noted we can use V 2.0.0.8 of the SigconArchitect.

    There are different video analyzer. You can check Tektronix, Omnitek, Phabrix, and Leader.

    For monitoring OUT0, you can use high speed real time scope.

    We have not experienced SMbus noise causing video error. If this is what is being experienced, then please check pcb layout to make sure there is no noise cross coupling.

    Regards,, Nasser

  • 0 in reply to Nasser Mohammadi
    Guru 36540 points

    Hi Nasser-san,

    Thank you for the information.

    I will ask our customer to use "SigCon Architect" and will contact you if I get additional questions from him.

    Best regards,
    Kato