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DS90UB927Q-Q1: [DAESUNG ELTEC] Inquiries about EMI issues

MJ Jeon
Genius 5240 points

Part Number: DS90UB927Q-Q1

Hi, TI Support Team

A customer is using the DS90UB927Q-Q1 product and is developing it, and there is an EMI issue.

You can check the detailed problem by looking at the attached file.

DS90UB927Q-Q1_EMI(RE) Issue Question_220421.xlsx

When measuring RE, noise in the 2.1GHz band is a problem that occurs in the FPD Link part.

What is the likely cause of the problem?

Is there any way to solve the problem?

Please help.

Thanks.

Regards,

MJ

  • 0
    Genius 5240 points

    Hi, TI Support Team

    Please also check the following inquiries included in the attached document.

    4. Question

    - Does TI have the same history as this phenomenon?

    - Is there a Spread Spectrum function for 'DS90UB927 FPD Link III Output (Pin 16, 17)'?

    - Is there a Strength Control function for 'DS90UB927 FPD Link III Output (Pin 16, 17)'?

    - Are there any other improvement methods using software settings?

    Thanks.

    Regards,

    MJ

  • 0 in reply to MJ Jeon
    TI__Mastermind 42090 points

    Hi MJ,

    Every customer's system are setup differently. The 2.1GHz is right on the 60MHz PCLK. What is the length of the cable from the head unit to the optical transmitter?

    Aaron

  • 0 in reply to Aaron Heng
    Genius 5240 points

    Hi, Aaron

    I will inform you about the customer's request as follows.

    “Even with the cable removed, that noise is generated.

    That is, it occurs in the head unit, regardless of the cable.

    We are going to conduct the EMI test again next Monday.

    Please check if there is a countermeasure using Software Setting (I2C).

    (Strength Control, Spread Spectrum, etc...)”

    The setting may be different for each customer, but are there any other reports of noise generation in the 2.1GHz band?

    Is there any way to lower the level of that frequency band?

    We are currently undergoing certification exams and are in an urgent situation.

    Please help.

    Thanks.

    Regards,

    MJ

  • 0 in reply to MJ Jeon
    TI__Mastermind 42090 points

    Hi MJ,

    Would it possible for you if you can use the near field probe? If you can, please probe at the device, AC coupling cap, CMC, cable and the connector. Do you see the same signature issue?

    Aaron