RF Emission issue using PTN3361

[garymitchell]

Hello NXP,  my name is Gary Mitchell and I have an RF emissions issue with a video cable.  The video cable incorporates a converter chip PTN3361.  This is used to convert a DisplayPort signal from a PC Core to a DVI signal at the monitor end.  I am seeing a peak emission at 540MHz.  Can you identify the source of this emission? Is there any way to prevent emission at this frequency? I am runnning 1280x1024 resolution to a 19 inch monitor. I notice david_diaz‌ had posted a reference design for DP to HDMI.  Do you have any experience of RF emission testing of circuits using this part PTN3361?

[reyes]

Hi,

Unfortunately no, we do not have any public document regarding the RF emission testing of circuits using this part PTN3361. But seems like the problem you are seen could be related to the layout design or cable you are using. there are some documents that can help you with the layout design:

AN10798 “DisplayPort PCB layout guidelines”: https://www.nxp.com/docs/en/application-note/AN10798.pdf

AN11397 “PTN3363/65/66 PCB layout guidelines”: https://www.nxp.com/docs/en/application-note/AN11397.pdf

Although the AN11397 is not designed for the PTN3361, it contains very useful information about how to properly design your layout for the HDMI/DVI signals, so I think it could be useful for your application.

I hope these documents can help since these are the only reference design/guidelines that we currently have.

Have a great day,
Jose

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