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HD3SS215: Inquiry about screen flickering phenomenon of HD3SS215 and request for schematic and PCB layout review

Grady Lee
Genius 4215 points
Part Number: HD3SS215

Tool/software:

Hi, TI expert

A customer is testing a 4K monitor with HD3SS215IRTQ and the screen flickers at 4K (38X0 x 2160@60hz) resolution.

- Application: 32” Surgical monitor

Q1) Can you confirm if there is any part that can be debugged in EQ function or F/W of HD3SS215IRTQ?

Q2) There is a TVS Diode (AZ1045-08F, Location: D25) connected to the part that connects to 44pin~54pin of HD3SS215IRTQR (Location: U21). It is said that the flickering phenomenon is slightly improved when the TVS Diode is removed. Is this related?

Q3) There was a model that applied HD3SS215IRTQR (Location: U21) before, but the IC was placed close to the front of the Scaler. When installed, the pattern of 1pin~12pin was short, but in this model, the IC location is slightly farther away, so the pattern length of 1pin~12pin has also increased slightly. However, it is said that the screen completely turns off when you touch the pattern of 1pin~12pin. Is there a problem with the pattern? 

Q4) I would like to request a review of the schematic and PCB layout.
I would like to proceed with the file privately, so if you tell me your e-mail address, I will send it to you separately by e-mail.

I would like to proceed with the file(schematic, PCB Layout) privately, so if you tell me your e-mail address, I will send it to you separately by e-mail.

Please check. Thank you.

  • 0
    TI__Mastermind 35638 points

    Hi Grady,

    Grady Lee said:
    Q1) Can you confirm if there is any part that can be debugged in EQ function or F/W of HD3SS215IRTQ?

    Not exactly sure what the ask is here. The HD3SS215 is a passive switch. There is not firmware. It acts as a resistor with some capacitance.


    Grady Lee said:
    Q2) There is a TVS Diode (AZ1045-08F, Location: D25) connected to the part that connects to 44pin~54pin of HD3SS215IRTQR (Location: U21). It is said that the flickering phenomenon is slightly improved when the TVS Diode is removed. Is this related?

    It could be. Where is the diode connected too? It could be just less capacitance, but the diode should only add 0.5pF to the load so I doubt it would make much of a real difference unless you've already overloaded the bus.


    Grady Lee said:
    Q3) There was a model that applied HD3SS215IRTQR (Location: U21) before, but the IC was placed close to the front of the Scaler. When installed, the pattern of 1pin~12pin was short, but in this model, the IC location is slightly farther away, so the pattern length of 1pin~12pin has also increased slightly. However, it is said that the screen completely turns off when you touch the pattern of 1pin~12pin. Is there a problem with the pattern? 

    I'm not sure what you mean by pattern here.
    Do you mean the layout? Yes, it could be a problem. You've added quite a bit of length so it could be the added parasitics you've added. 

    Grady Lee said:
    Q4) I would like to request a review of the schematic and PCB layout.

    Sure, you can send it through the E2E messages. I'll take a look but for something like this, debugging on the board directly may be the best option. However, it will be hard to confirm if it is something like overloading the bus. That being said, Why is the mux the thing being viewed as the issue? Have we bypassed the mux to see how the signals look with vs without the mux?

    Thanks,
    Rami

  • 0 in reply to Rami Mooti1
    Genius 4215 points

    Dear, Rami

    Thank you for response.

    I sent the schematic & PCB layout to you through private massage.
    Please review it.

    Please check. Thank you.

  • 0 in reply to Grady Lee
    TI__Mastermind 35638 points

    Hi Grady,

    Nothing stood out to me as wrong with the schematic. Like I mentioned, especially given that it was working in a different design but caused issues with the blinking after the traces were extended, It could very well be that the extra trace parasitics is causing issues. It's a fairly simple device so there's not much more that can affect the signal from the mux side. 

    Thanks,
    Rami