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DLPC350: Power On Sequence

Kiyong SON
Intellectual 545 points
Part Number: DLPC350


Dear TI-er

My customer have a issue because of the area.

Q1) what's the problem 1.2V Core, I/O, FPD at the same time
Q2) 2.5V power whthout the timing ?
Q3) Termination resistor is 50ohm in the datasheet. Can I use 22ohm ?

DLPC350ZFF Datasheet Power Recommendations (42page)

normal sequence in the datasheet

Customer's sequence (red line)

  • 0
    TI__Expert 7035 points

    Hello Kiyong,

    Welcome to the E2E forum and thank you for your interest in DLP technology!

    Is the customer using this product with a TI EVM or is it a custom board? Is there a certain condition that causes the issue? Can you give more detail on question 2?

    Regards,

    John

  • 0 in reply to John McKnight
    Intellectual 545 points

    Dear TI-er

    Refer to customer's board with red line sequence.

    Q2 is no problem. only timing sequence exept 2.5 voltage.

  • 0 in reply to Kiyong SON
    TI__Genius 12795 points

    Hello Kiyong,

    1. Q1: This is described in section following the timing diagram you provided from the DLPC350 Datasheet. Please refer to Section 10.1.2 and the first bullet in the second section. In short, the core should be applied before IO and other supplies to ensure that pins are set to a known state.
    2. Q2: I am not sure I understand this question. Is a power rail operating at 2.5V instead of another voltage specified? This is not recommended and may greatly impact the DLPC performance.
    3. Q3: Which termination resistor are you referencing here? Why would the customer prefer 22ohm in place of 55ohm? In general, this is not recommended. It may alter the transition times or amplitude of the signals.

    Kind regards,

    Austin

  • 0 in reply to Austin Snyder
    Intellectual 545 points

    Dear TI-er

    Sorry for it.

    Q3) Termination resistor is 5 ohm in the datasheet. Can I use 22 ohm ?

  • 0 in reply to Kiyong SON
    TI__Mastermind 23090 points

    Hello Kiyong,

    We will get back to you by middle of next week. 

    regards,

    Vivek

  • 0 in reply to Kiyong SON
    TI__Expert 3825 points

    Hello Kiyoong,

    In regard to Q1) what's the problem 1.2V Core, I/O, FPD at the same time

     Although it is recommended that the ASIC Core, 1.2V, be brought up first, as shown in Figure 21.

    It is not a requirement. Per Section 10.1.2 from spec, shown below, there are no specific power-up order restrictions.

    Also, the POSENSE should not go High until all of the voltages are up.

    The ASIC does not start any initialization until after POSENSE goes high.

    In regard to Q3) Termination resistor is 5-ohm in the datasheet. Can I use 22ohm?

    Per the following paragraph in section, 11.1.1 DMD Interface Design Considerations

    Yes , you can use 22-ohm series termination in place of the 5-ohm series resistor in the DMD signal lines referenced in section 11.1.2. But Note that the verification of signal timings for this change are not verified from us.