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SN65HVD233-EP: ibis file vih, vil doesnt match datasheet

assaf matia
Prodigy 240 points
Part Number: SN65HVD233-EP
Other Parts Discussed in Thread: SN65HVD233

Tool/software:

Hi,

in the ibis file (for sn65hvd233) the vih, vil of driver in (D) is vih=2.4V, vil=0.4V

in the datasheet for both sn65hvd233 and sn65hvd233MDREP the vih id 2V and vil is 0.8V

which is correct? 

and does the ibis of sn65hvd233 can be used for  sn65hvd233MDREP?

  • 0
    TI__Guru 74252 points

    Assaf,

    To answer your second question, yes, the same IBIS model can be used for both. 

    For the VIH and VIL of the driver, the datasheet is showing the worst cases for both maximum of VIL and minimum of VIH. These are based on CMOS logic structure, and the IBIS model was likely designed this way to meet the correct timings for the output waveforms. Since they are both skewed by the same absolute amount, it seems like this was done to allow for the correct propagation delay within whichever simulator was used to design and test the IBIS models. Since this is a relatively old device, the engineers who designed and tested this are no longer within our group, so I can't get a definitive answer, but that is what I've seen done with other IBIS models. 

    I know that was a fairly vague answer, but if you need more information I can go back to our design team to see if they have more insight.

    Regards,

    Eric Hackett 

  • 0
    Prodigy 240 points

    so, can i understand that the datasheet is yhe valid soec fir the devuce? ibis is just for signals simylation and not a valid vih vil limits? 

  • 0
    Prodigy 240 points

    so can i understand from this, that the datasheet is the valid spec for vih vil? ibis just for signal integrity and not as vih limits in the simulation plot (you can put in hyperlynx the vih , vil limits to see how the signal looks relative to yhem.) so in ibis i will ignore the ibis vih vil and use the datasheet as the real valid threshold? 

  • 0 in reply to assaf matia
    TI__Guru 74252 points

    Assaf,

    This is correct, but keep in mind the datasheet is the absolute worst case, and in reality the thresholds are higher/lower, respectively, in a system. But, design should still consider the worst case.

    Regards,

    Eric Hackett