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DLP9000: PCB routing of single-ended signals between DLPC900 and DLP9000 devices.

Part Number: DLP9000
Other Parts Discussed in Thread: DLPC900

Hi,

I am designing two boards, one which uses two DLPC900s, and another with the DLP9000. I have routed the differential pair tracks for length, width, spacing, etc. as indicated in the DLPC900 spec. But for the single-ended signals, I see very little in terms of recommendations. Specifically for the DAD* signals:

1) Is there a maximum length requirement?

2) For my calculations, shall I assume that these are 200MHz signals? Are they something less than that?

3) Do these signals need to be length-matched with each other?

4) Spec says 50Ohm impedance, but some signals have a 470Ohm termination on the DMD side. What is that for?

Thanks,

Hanson

  • Hello Hanson,

    I am on travel.  Please allow a couple of days for me to get back to you on this one.

  • Hello again Hanson,

    1) Is there a maximum length requirement?

    Our designer indicates that at the lower speeds that length matching is not critical nor is maximum length.

    2) For my calculations, shall I assume that these are 200MHz signals? Are they something less than that?

    For the SCP signals 200 MHz is overkill these signal are about 1000 time slower.  200 kHz would be sufficient.

    For the "DAD" signals 25 MHz is more than adequate.

    3) Do these signals need to be length-matched with each other?

    See the answer to 1).

    4) Spec says 50Ohm impedance, but some signals have a 470Ohm termination on the DMD side. What is that for?

    This could look like a series termination, but it is actually intended as a filter after the flex cable.

    I hope this helps.

    Fizix

  • Hi Fizix,

    Thanks for those answers. For #4, is that 470 Ohm value specific to the Amphenol flex cable (I'll be using a different cable in my design)? It's probably a dumb question, as I'm more of a digital ASIC guy than anything else.

    Best,

    Hanson

  • Hello Hanson,

    Further investigation by our team found this note (from the schematic):

    R6 must not be eliminated, which is used with C111 to delay the OEZ input.

    Fizix

  • Sounds great, thank you!

    Hanson