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TINA/Spice/AM3352: USB IBIS model

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Replies: 7

Views: 213

Part Number: AM3352

Tool/software: TINA-TI or Spice Models

Part Number: AM3352

Hi,

I am simulating USB1 data signals in HyperLynx 2.4 using ibis model provided by ti.

For USB1 data signals model is defined as NC in ibis model, so at the time of assigning model i cannot select it as output(refer below images).As it is data signal i can define any connected IC as output driver but my problem is signal is passing through Common Mode Filter with ESD Protection for that i have assigned S-parameters then to connector which is also defined as input only.

So, at the time of simulation I get error of No output driver selected.

I have tried to change the ibis model by changing model to selector, but in that case though it is allowing me to define it is as output  I get my output according to selector pull-up defined(1.5V  or 1.8V or 3.3V) and not the expected (400mV) signal.

suggest me how to define R17 and R18 pins of AM3352 as I/O or which selector should i select as all selector are having pullups defined ? Please send updated ibis model for these two pins defined as I/O.

  • Hi Ronak,

    FYI, one of our team member will take a look at this.

    Herman

  • Hi Ronak,

    These are listed as analog pins in the datasheet. As such, they are not suitable for IBIS models.

    I'm not sure why those pins are listed as analog. Perhpas there's some de-emphasis, which would not make them appropriate for IBIS modeling (prior to AMI).

    Page 78 briefly mentions USB0 and USB1, but those pins are not described in the digital spec portion of the datasheet.

    Regards,

    David

  • In reply to David Larkin - WEBENCH Design Center:

    Hello David,

    I don't have source to drive USB data signals on my PCB as it will be sourced from device connected at connector side.

    For Simulation of routing from connector to SOC what can i do? Like dummy component at the connector side would be helpful or not?

    Regards,

    Ronak.

  • In reply to Ronak Parmar:

    Hi Ronak,

    I checked with my co-worker, and his experience is that these buffers were often not modeled due to their complexity.

    As such, we have no model for them.

    It's unlikely that any related devices will have model since they would share the same standard cells.

    Given that these are input pins, they are high impedence, with low capacitance. You should be able to get the capacitance of the pins from the datasheet.

    You could try using that as your model if nothing else is available.

    Regards,

    David

  • In reply to David Larkin - WEBENCH Design Center:

    Hi David,

    By default configuration in our mode for both USB pin is high input impedance what you are suggesting.

    Is there any another way as we can configure those pins as I/O ?

    Can you share some dummy model to simulate USB2.0 signals?

    Thanks,

    Ronak

  • In reply to Ronak Parmar:

    Hi David,

    Please do the needful.

  • In reply to Ronak Parmar:

    Ronak,

    Please read  The status is the same at present. Also there are some recommendations here: processors.wiki.ti.com/.../AM335x_Schematic_Checklist

     

    Best Regards
    Biser