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DS90UB928Q-Q1: two question from datasheet

Amelie Zheng
Genius 10865 points
Part Number: DS90UB928Q-Q1

Hi Team,

Regarding the use of the DS90UB928Q-Q1 IC, there are two questions I would like to ask:
1. Regarding the output of the LVDS interface, the datasheet mentions that a 100Ω resistor needs to be placed on the N/P. Is this resistor only used when the chip does BIST self-test? The package uses 0201, can customer use 0402? Due to the pads, the impedance of the traces may be discontinuous. Customer want to remove these 5 resistors. If removing, they can't do BIST, right? If they don't want to do BIST in their product, could they remove?

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2. Customer's  display screen is 480*480, and the frame rate is temporarily uncertain. If calculated at 60Hz, is TxCKL approximately equal to 480*480*60≈13.82M? Combined with the specification, should they set LFMODE to high ?

  • 0
    TI__Guru 66810 points

    Hi Amelie,

    Amelie Zheng said:
    1. Regarding the output of the LVDS interface, the datasheet mentions that a 100Ω resistor needs to be placed on the N/P. Is this resistor only used when the chip does BIST self-test? The package uses 0201, can customer use 0402? Due to the pads, the impedance of the traces may be discontinuous. Customer want to remove these 5 resistors. If removing, they can't do BIST, right? If they don't want to do BIST in their product, could they remove?

    Are you talking about the 100ohm termination resistors on the OLDI outputs? These are typically embedded inside the connecting panel/device that is receiving the OLDI signals. So these do not need populated on the actual 928 PCB generally.

    Amelie Zheng said:
    2. Customer's  display screen is 480*480, and the frame rate is temporarily uncertain. If calculated at 60Hz, is TxCKL approximately equal to 480*480*60≈13.82M? Combined with the specification, should they set LFMODE to high ?

    Correct, this is the PCLK of the video.

    Regards, 

    Logan