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Creating IBIS models for older components...

Ramzi Vincent
Prodigy 50 points
Other Parts Discussed in Thread: SN74ACT245, SN74ACT244

I did some looking around in the TI IBIS zip file and couldn't find the associated IBIS models, so here goes.


SN74ABT241: ADW package

SN74ACT240: DW package

SN74ACT241: DW package

SN74AC241: DW package

I tried using Mentor's Visual IBIS editor, but was cautioned against using it's wizard.  Is there a better way?  or perhaps a repository of files that I don't know about?


While I'm at it, what's the best way to create a model for ASICs?

  • 0
    TI__Genius 12740 points

    Hi Ramzi,

    SN74ACT244 and SN74ACT245 have IBIS models. They are both Octal bus transcievers with 3-state outputs. Can you see if this model is suitable for your simulations?

    The SN74ABT241 is obsolete, so we won't be able to support that device with a model.

    Regards,

    David

    Webench Design Center

  • 0 in reply to David Larkin
    Prodigy 50 points

    I'm kinda new to using BoardSim which is a Mentor product.

    From what I gather, a device with a similar package can supply the R, L, C numbers for the pins while a device similar in function can supply the other stuff.  So I suppose I'll ask if you believe those two parts you listed are similar enough in function, especially for a low frequency system (16 MHz and lower)...

  • 0 in reply to Ramzi Vincent
    TI__Genius 12740 points

    They share the same package, and basic design. I've cobbled together a model for the ACT241 and attached it to this post. Let's see if I did that correctly.

    Looking at the datasheet, the spec's on the VOH/VOL as well as the Tr/Tf suggest that this model should be fine. There's a bit of a difference on the Co capacitance, but at 16 MHz, this won't matter.

    David

    sn74act241.ibs
  • 0 in reply to David Larkin
    Prodigy 50 points

    OK.  So you're suggesting that one model is good to use in place of all four part numbers I listed (because the packages are the same)?

  • 0 in reply to Ramzi Vincent
    TI__Genius 12740 points

    The model should be good for the ACT240 and ACT241. The AC240 shows and extended voltage range. The model provided only covers VCC = 5.0.

    The ABT241 is obsolete, so I'm not sure if it shares the same circuit architecture or not.

    David