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TS3USB221: Hyperlynx simulation with TS3USB221 multiplexer

William Greenwald
Prodigy 30 points
Part Number: TS3USB221

I am fairly new to Hyperlynx (Mentor) PCB simulation.  The PCB that I am simulating includes the USB MUX TS3USB221, for which I have downloaded its IBIS model file.  The model has been assigned to the part on the PCB and a LineSIM schematic has been exported with the selected nets.  My resultant simulations seem to show that the MUX part does not pass the D+ and D- signals through it so I can measure and record the waveform at the end of the path.  I am very fuzzy on how this part's IBIS file is supposed to work and what other device pins need to have inputs on them to enable the desired "virtual" switch defined by the file.  I would greatly appreciate any insight and help with this issue.  Thanks.     Bill Greenwald (DEKA Research)

  • 0
    TI__Guru*** 140195 points
    William

    Please see this e2e thread: e2e.ti.com/.../657422.

    In the TS3USB221 IBIS model, *_S is the switch model for both 2.5V(commented out) and 3.3V.

    Thanks
    David
  • 0 in reply to David (ASIC) Liu
    Prodigy 30 points
    Yes, I know that those submodels are included in the IBIS file, however, once the file has been assigned to the part in the PCB, there is no way to change the pins to anything other than "input", and there is no way to select any of the different internal models. I guess I must edit the IBIS file to remove any model that is not a "switch". Sadly I will only be guessing at what to edit.
  • 0 in reply to William Greenwald
    TI__Intellectual 2140 points
    Hi William,
    This seems to be a Hyperlynx set up question. I found the below from previous e2e thread that might be able to help you.
    If it doesn't work, I suggest you contact Hyperlynx support for further instruction.
    Thanks,
    -Eric


    ***************************************************************************************************************************************************************************
    The following is a brief instruction on how to properly set up a switch model in Hyperlynx. Please give this a try and let us know how it goes:
    ***********************************************************************************************************************************
    1) You’ll need a driver and a receiver to connect the switch to.
    2) Place a MOSFET series, it’ll be on the left and looks like a CMOS.
    3) Select Models – Assign Models/Values by Reference Designator (.REF file)…
    4) In the Design’s parts list, select your component (e.g. U1), under Model/value, go to .IBS, and look around for your ibis file that has the switch model.
    5) Once selected, click on Assign Model, save your .REF file and close this window.
    6) You can then either double click on the box, or select and the go to Models – Assign Models/Values by Component.
    7) In this menu, choose a pin for connectivity. It should select the matching pin based on the model.
    8) Connect to your transmitter device and receiver and you can simulate.
    ****************************************************************************************************************************
  • 0 in reply to Eric Kim- DSS
    Prodigy 30 points
    Eric;
    I appreciate your willingness to discuss this issue. I, however, am not convinced that it is a Hyperlynx problem. There are 2 obvious possibilities. One is Hyperlynx, which is supposed to be IBIS Series component compliant, MOSFETS, Resistors, ETC. The other is TI's IBIS file. It may be broken, and not implement the Series MOSFET function and it's control pin properly. My PCB has resistors that bypass this MUX part, and they pass the signals just fine. I have added pullup and ground to the control pins on the MUX, but they don't do anything. There is an output enable pin and a select pin. They don't work as I know they would on the actual device. So, what I need is expertise with the operation of IBIS files and the implementation of the these series switches. Know that I am always in contact the the Hyperlynx people and I will be feeding them this new "experience" information.
  • 0 in reply to William Greenwald
    TI__Intellectual 2140 points
    Hi William,

    Did you get a chance to follow the instruction and was able to simulate the IBIS model? That will be the first thing to check.

    Regards,
    -Eric