This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

SN74CBTLV3257: IBIS Model for RGY Package

Part Number: SN74CBTLV3257
Other Parts Discussed in Thread: SN74LV4066A, TMUX1574

Hi Team,

Do we have an IBIS model for the RGY (VQFN) package of SN74CBTLV3257? The IBIS model in the website seems to include the other packages but the RGY package.

Thanks in advance!

Kind Regards,


  • Hey Jejomar,

    We don't seem to have the VQFN IBIS model for the SN74CBTLV3257. 

    The differences between packages is fairly marginal so I wouldn't see a problem with using the other packages. 
    That being said, if you'd like to get as close as an approximation as your model may allow, you can change your values to the following: 

    |                 typ        min                         max
    R_pkg     2.900e-02     2.300e-02     4.100e-02
    L_pkg      7.730e-10    6.570e-10    9.980e-10
    C_pkg     1.360e-13     1.150e-13     1.560e-13

    I pulled this from the SN74LV4066A IBIS model where the pin parameters for the RGY were listed. The other pin specs are listed in that model as well, and you could pull those as well if you'd like. The packages will vary your Ron by at most a few mili-ohms, the inductance by a matter of a couple of nH, and capacitance a fraction of a pF. If your design is that dependent on a change so small, I would recommend a different part.

    On that note though, have you taken a look at the TMUX1574? It's a newer 4 channel 2:1 device we have that is 1.8V logic compatible with upgraded functionality. It won't come in the VQFN package but the UQFN is a bit smaller.