SN75DP139: SN75DP139 EMI issue

Jason Chien42

Part Number: SN75DP139

Dear Sir:

We used SN75DP139 for mini DP to DVI cable application and it over EMI limit as below picture. Does TI have suggest to us?

over 7 years ago

0 David (ASIC) Liu over 7 years ago

TI__Guru**** 183501 points

Jason

Have you done TDR to see if there is any impedance discontinuity?

Thanks
David

0 Hugo Liu over 7 years ago in reply to David (ASIC) Liu

Genius 5095 points

Hi David,

The following is impecdance test report, this is meet spec 95~105 ohm, and Diagram for your referene.

Do you have any idea to slove the EMI issue?

0 David (ASIC) Liu over 7 years ago in reply to Hugo Liu

TI__Guru**** 183501 points

Hugo

Besides the cable impedance, do you have the DP139 PCBA impedance? Is there a way to measure the PCBA EMI without the cable?

You can also add 10pF and 4.7pF caps on DP139 3.3V power supply and see if it helps improving the EMI performance.

Thanks
David

0 Hugo Liu over 7 years ago in reply to David (ASIC) Liu

Genius 5095 points

Hi David,

Thanks, we will disscuss with customer.

Hugo

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SN75DP139: SN75DP139 EMI issue