SN75DP139: SN75DP139 Rvsadj is 3k

Shu-Cheng LIN

Guru 11785 points

Part Number: SN75DP139

Hi Sirs,

Sorry to bother you.

Our HDMI eye pattern will failed even Rvsadj use 3.65k, but it's be passed when use 3k

So we would like to know have any risk if we use 3k Rvsadj?

Thanks!!

over 7 years ago

0 David (ASIC) Liu over 7 years ago

TI__Guru**** 184121 points

Shu-cheng

How long is your trace length from SN75DP139 output to the HDMI connector, and how long is the cable from HDMI connector to the scope?

At 3.5K, the amplitude is ~1.25V, I am trying to understand why you are having a huge signal amplitude loss.

Thanks
David

0 Shu-Cheng LIN over 7 years ago in reply to David (ASIC) Liu

Guru 11785 points

Hi Sirs,

Please refer my update as below

How long is your trace length from SN75DP139 output to the HDMI connector,

2000 mil

and how long is the cable from HDMI connector to the scope?

Under 1m cable

0 David (ASIC) Liu over 7 years ago in reply to Shu-Cheng LIN

TI__Guru**** 184121 points

Shu-Cheng

Please do not use the 1m cable when doing the HDMI compliance testing as the cable will negatively impact the compliance result.

Please see this link: www.wilder-tech.com/.../hdmi for HDMI breakout test fixture.

I also sent you a friendship request. If needed, I can review your layout to see if improvement can be made to the signal path between the DP139 and HDMI connector.

Thanks
David

0 Shu-Cheng LIN over 7 years ago in reply to David (ASIC) Liu

Guru 11785 points

Hi David,
I don't use cable on HDMI compliance testing
We use test fixture + carbon rod to the oscilloscope directly
I've send our schematic and layout for you reference, any suggestion are welcome
By the way, have any risk if Rvsadj is 3k?

0 David (ASIC) Liu over 7 years ago in reply to Shu-Cheng LIN

TI__Guru**** 184121 points

Resolve issue through direct support, close the thread.

Thanks
David

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SN75DP139: SN75DP139 Rvsadj is 3k