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ADS Treatment of IBIS Models of Type I/O

Question asked by JohnMM on Jun 15, 2018

Hi,

  This question pertains to ADS' handling of IBIS models of type I/O. If I create a schematic and select the "Signal Integrity - IBIS" pallet, I can't seem to find a component that will let me specify the direction of the pin as input for a pin associated with an IBIS model of type I/O. I've tried IBIS_Pin, IBIS_T, IBIS_I, IBIS_O, and IBIS_IO.

 

  For IBIS_Pin and possibly some of the other components just cited, I would expect that the tool would ask me whether I want the pin to be an Input or and Output for model of type I/O. It seems like ADS is defaulting to Output since it always puts the pin on the output side of the buffer. Nowhere does the tool ask me whether I want the I/O pin type to be Input or Output.

 

  My apologies in advance for comparing ADS to the competition (Hyperlynx) but their treatment of I/O model types seems rational to me. HL, after associating an IBIS model of type I/O with their buffer symbol, then lets you choose whether the pin is Input, Output, Output Inverted, Stuck High, or Stuck Low. If you select Input, the buffer symbol changes to reflect that selection, i.e. pin on input side of buffer.

 

  What do I do if I want a pin of type I/O to behave as an Input in ADS?

 

Thanks,

John Morton

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