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DS90UB953-Q1: Request 953 Circuit Review

choi donghun
Prodigy 100 points
Part Number: DS90UB953-Q1

Hi, there

I revised the circuit as the guide last time.

Please review the circuit again.(I attached a circuit)

And I organized the questions into PPT, so please answer them.

LG_FORD_RGBIR_OV2778_MAX20446_R73_211122_ICC.pdfTI Question.pptx

Thanks

  • 0
    TI__Mastermind 27920 points

    Hi Choi,

    I can review your schematic and provide answers to your questions. I will return with a response by the end of next week (12/3).

    Best,

    Justin Phan 

  • 0 in reply to Justin Phan
    TI__Mastermind 27920 points

    Hi Choi,

    I have a question that can help with my schematic review. What compatible deserializer will the UB953 be connected to? I see a discrepancy in the schematic and need to know the intended Forward Channel data line rate.

    Best,

    Justin Phan

  • 0 in reply to choi donghun
    TI__Mastermind 27920 points

    Hi Choi,

    Got it, thanks.

    I will still need a few days to finish the review. But the reason I asked is because you are using a 25MHz, but you would need a 50MHz clock at the CLKIN pin in order to achieve a FC bit rate of around 4Gbps. And the UB954 operates at 4Gbps in Non-Synchronous mode. 25MHz clock is used when using a DVP deserializer, such as the UB934 or UB914A.

    I will include more details in my comments once I finish, but feel free to see the "Non-Synchronous external clock" entry in "Table 7-6. Clocking Modes" in the UB953 datasheet for more details right now.

    Best,

    Justin Phan 

  • 0 in reply to Justin Phan
    TI__Mastermind 27920 points

    Hi Choi,

    I have completed my review. However, there are a few points that I've asked clarifying questions on. See my comments in the PDF and my responses in the PowerPoint. And let me know if you have any questions.

    LG_FORD_RGBIR_OV2778_MAX20446_R73_211122_ICC_Reviewed.pdf

    TI Question_12-1-2021.pptx

    Best,

    Justin Phan

  • 0 in reply to Justin Phan
    Prodigy 100 points

    Hi Justin,

    I'd like to update to your TI Question pptx above, and I attached my comments as Green lines.

    Please check my comments and question, and if possible, confirm some item as much as you can.

    TI_Question_12-1-2021_Reply.pptx

    FYI, as you mentioned before in the ppt file - the NDA thing - I don't know your e-mail, so I just attached NDA file.

    It's NDA with TI Korea agency(Arrow) , so I hope there's no issue that you forward your internal document.

    Regard,

    Choi donghun

  • 0 in reply to choi donghun
    TI__Mastermind 27920 points

    Hi Choi,

    Here are my responses in the attached PowerPoint.

    TI_Question_12-1-2021_Reply_12-9-2021_TI-Reply.pptx

    Has your customer signed an NDA directly with TI? I am trying to verify if the document you've provided for me is able to cover TI FPD-Link parts, but it seems to be with Arrow instead. 

    What I am looking for is something like "NDA ID", "NDA Type", "Status", and the specific customer name, so that I can look it up in our TI NDA database.

    I also can't share any NDA materials here in this public forum, so please click on my name and private message me your email if you would like to discuss NDA materials offline. 

    Best,

    Justin Phan

  • 0 in reply to Justin Phan
    Prodigy 100 points

    Thanks for your detailed reply.

    I'll update the "ppt" after I update some comments, but one more thing about PoC Filter.

    I'm looking for the 2G PoC Filter with Non-sync mode(using 25MHz OSC).

    Can you guide the Filter with up to 125ºC(ambient temp) inductors?

  • 0 in reply to choi donghun
    TI__Mastermind 27920 points

    Hi Choi,

    If you are pairing a UB953 with a UB954 in Non-Sync Mode, then the Forward Channel Line Rate will be determined by the external oscillator frequency at the CLKIN pin on the UB953. The frequency of the oscillator is defined in "Table 7-6. Clocking Modes" and the "FC DATA RATE" equation is there too.

    Depending on if you use a 25MHz or 50MHz oscillator at the UB953 CLKIN pin in Non-Synchronous Mode, the FC rate will change and the required PoC network will change. If you use a 25MHz CLKIN input at the UB953, then the FC rate will be about 2Gbps (~1GHz). In Non-Synchronous Mode, the BC line rate is fixed at 10Mbps (5MHz). Your PoC network must be able to provide >=2-kOhms over the frequency band of the FC and BC (5MHz - 1GHz). And your system must also still be within the channel specifications (Return Loss, Insertion Loss, etc...) for normal operation. See the related device datasheets for more details.

    An alternative is to set the UB953/UB954 to Synchronous Mode, where the UB954 will send a clock over the back channel. This allows you to not need an external oscillator on the UB953 side. The default FC line rate will be 4Gbps, but it is possible to lower that FC rate to 2Gbps. See this thread here for more details: https://e2e.ti.com/support/interface-group/interface/f/interface-forum/905709/ds90ub954-q1-how-to-set-953-954-at-2gbps-half-of-full-speed-in-syn-mode?tisearch=e2e-sitesearch&keymatch=953%252520clkin%25252025MHz# 

    The "2G" PoC circuit defined in the UB954 datasheet has the same current and temperature rating as the "4G" PoC circuit. It is rated up to 150mA current and 105 degrees Celsius. If you would like to modify the design to achieve a higher temperature rating, then I recommend contacting the coil vendor or other component vendors for additional help in replacement parts (Coilcraft/TDK/Murata). But you would still need to verify through simulation or physical measurements that the channel specs are met in the modified design.

    I can only provide comments on the publicly available PoC networks here. If you can provide proof of NDA with TI, then we can discuss more offline regarding internal PoC designs. 

    Best,

    Justin Phan