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SN74AVC4T774: IBIS model issue

Chun-Chen Liu
Prodigy 20 points
Part Number: SN74AVC4T774

Hi TI 

I try to use "SCEM539.ZIP (63 KB) - IBIS Model"  for simulation and find it is 0.7v operation type

www.ti.com.cn/.../SN74AVC4T774

Can you help to provide the 3.3V model as our schematic design

If no 3.3V, please help to confirm the different of I-V characteristic curve between 0.7V, 3.3V model

Thanks

  • +1
    Guru 243220 points

    The IBIS model contains data for 1.2 V, 1.5 V, 1.8 V, 2.5 V, and 3.3 V supplies.

    The only occurrence of "0.7 V" in this model is the Vinl parameter for 2.5 V. This parameter describes the maximum input voltage that is a valid low-level input.

  • 0 in reply to Clemens Ladisch
    Prodigy 20 points

    From the description in this IBIS model:

    | - Model names with a trailing _0p7 contain the model for 0.7V operation.
    | Model names with a trailing _1p8 contain the model for 1.8V operation.
    | Model names with a trailing _3p3 contain the model for 3.3V operation.

    And I think this is a "input_0p7 Model" type

    Please help to provide the "input_3p3 3.3V digital Input" type 

    Thanks

  • 0 in reply to Chun-Chen Liu
    Guru 243220 points

    I cannot find that text in the IBIS model file.

    The scem539.zip file has a size of 64673 bytes; the sn74avc4t774.ibs file, 399850 bytes. Do you have some other version of this file?

  • 0 in reply to Clemens Ladisch
    Prodigy 20 points

    I download the scem539.zip file again and find the latest file is "IBIS Ver 3.2 (December 11, 2009) " which is old version

    What I had already downloaded is "IBIS Ver 4.1 (04/15/2019) " and full description is:

    [Notes] Revision History:
    | Rev 1.0: 04/15/2019
    | - Initial version of the model
    | - Model generated from simulations in SPECTRE
    | - C_comp although listed in numerical order of value are
    | obtained from varying PVT conditions. For PVT conditions for
    | each specific value refer the buffer description under
    | respective [Model]. IBIS model user is responsible for using
    | appropriate C_comp to simulate for Signal Integrity.
    | - Warnings regarding combined Non-monotonicity of various models have been
    | reviewd and considered minor and can be ignored.
    | - Model names with a trailing _0p7 contain the model for 0.7V operation.
    | Model names with a trailing _1p8 contain the model for 1.8V operation.
    | Model names with a trailing _3p3 contain the model for 3.3V operation.

    Please help to double check this information, thank you

  • 0 in reply to Chun-Chen Liu
    Guru 243220 points

    That file is not contained in scem539.zip but scem589a.zip, which is for a different device, the SN74AXC4T774.

    Anyway, both IBIS files contain data for 3.3 V supplies.