something wrong about TVP5158 output

Jin Yibin

Other Parts Discussed in Thread: TVP5158

Hi,I have a customized Board (TVP5158+DM6467),when I force TVP5158 output a bluescreen or set it as 2CH D1 line mode, I found a 27MHz clock coupled to the TVP5158 output . If I disable TVP5158 output ,the 27MHz clock is gone as well as the output data .the attachment are waves i save ,

I do not know where this aggressive 27Mhz signal comes from.

over 15 years ago

0 James Nave over 15 years ago

TI__Expert 6120 points

Hello Jin,

This is most likely a board schematic and/or layout issue.

Please provide a pdf file of your schematic.

Regards,

Jim

0 Jin Yibin over 15 years ago in reply to James Nave

Intellectual 740 points

3324.VIDEOCAPBOARD.pdf

Hi ，James，schematic is attached,thanks

0 James Nave over 15 years ago in reply to Jin Yibin

TI__Expert 6120 points

Hello Jin,

Recommend using split ground planes (AGND/DGND).

Recommend adding a large tantalum capacitor after the inductor on the analog supplies (e.g. AVDD11, AVDD18_AD, AVDD_AD). A good rule of thumb is to use at least 10x the sum of the ceramic capacitors.

Recommend reviewing the TVP5158 PCB layout guidelines.

http://www.ti.com/litv/pdf/slea073a

Regards,

Jim

0 Adauto Luis over 13 years ago in reply to James Nave

Prodigy 10 points

Hi James,

I'm experiencing the same issue described by Jin Yibin. However, I'm using the tvp5158evm.

Do you think it could be something with the tvp5158 configuration ?

Adauto

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something wrong about TVP5158 output