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TXS0104E: Signal Integrity

Shinu.V.Mathew
Expert 8225 points
Part Number: TXS0104E
Other Parts Discussed in Thread: TXS0101

Hi Team,

One of my customer is using TXS0104E  and observing issues with Signal Quality and signal Transition with Level translator usage in simulation.

Please note the issue Exist :  Even if  you connect  MCU , Level shifter , NOR  alone Ignoring(removing) all other transimission line , Via, terminations effect etc.

They are using Mentor Graphics Hyperlynx 9.4.1 and attached is the simulation waveforms and details.

Can you please look into the issue and let us know if there are known issues with the IBIS for this (TXS0104EQPWRQ1) part.

Also suggest solution for the same.  IBIS Model used is Embedded in the Design.

MCU NOR_12Jun2018_TI.PPTX

Regards, Shinu Mathew.

  • 0
    TI__Mastermind 45145 points
    Hi Shinu,

    I don't believe there are any known issues for this Ibis model, but i am going to assign this post to our translation expert to assist you with this.
  • 0
    TI__Guru 59770 points

    Hi Shinu,

    We have recently got in a request on this device model.

    The modelling team is looking into it currently. They believe that the model is not fully representing the TXS0104 behaviour.

  • 0
    TI__Guru 59770 points
    You could consider using one of the other TXS models to see if it can satisfy the simulation requirement.
    the internal structure of the TXS0101/2/4 are similiar to each other.
  • 0 in reply to ShreyasRao
    TI__Expert 8225 points

    Hi Shreyas,

    Thanks for the input s and support.

    Customer simulated with TXS0101/2 model and have few queries as below,

    •         If the level translator is pass through switch ? or the Regenerating  type?

    •         If it is pass through switch the delay is not included in the IBIS model.

    •         We observe that  the level shifter is regenerating the signal at 0 ,  do not see the delay between input to output.

    Can you please clarify on this

    Why the model is regenerating ?

    Why the prorogation delay is not included in the model?

    In the below snapshot 3.3v is controller output, if you notice the level translator output is appearing earlier than Controller output.

    Regards, Shinu Mathew

  • 0 in reply to Shinu.V.Mathew
    TI__Guru 59770 points
    Hi Shinu,

    what do you mean by regenerating?
    TXS is a switch based translator device which passes through the low signal as it is, and the high signal is pulled up through the combination of oneshot and the pullup resistor.
    The low signal will have minimum prop delay.
    hope it answers your question.

    Application note for the TXS device is here below :
    www.ti.com/.../scea044.pdf
  • 0 in reply to ShreyasRao
    TI__Expert 8225 points

    Hi Shreyas,

    Thanks for the reply.

    If the part is switch (pass thru ) type then why are we observing the output of the level shifter is getting regenerated (appearing earlier than driver)?

    Can you plaese look into attached IBIS model, I don’t see any parameter/indication that this part is a pass thru switch type.

    The input requirement of NOR (Rxr) is  Maximum rise time is  1.5ns.

    Also the part you suggested has higher rise time and fall time at output.

    TXS0102 Model.zip

    Regards, Shinu.

  • 0 in reply to Shinu.V.Mathew
    TI__Guru 59770 points
    Shinu,

    I believe that this is an error. The output cannot show up before the input while passing through a device.
    Please submit the error to the IBIS modelling team in the simulation models forum.
    I will also let them know about this.