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TINA-TI: Macro Model Problem

Part Number: TINA-TI
Other Parts Discussed in Thread: REF3440, REF3430,

Hello,

I would like you to confirm about below.

* Now we are using TINA-TI macro for REF3440 and REF3430. However, it seems that both have problem.

Now, I tried to generate following circuit.

And after that, I performed DC analysis. Then output show impossible result on this cirucuit.

* Input voltage is 5V, but force output show 10.5V.

Same result can be observed on REF3440 as well. This macro model is encrypted model, so I can't show detail of macro. Therefore, could you please check macro model ?

Best Regards,

  • Hi Machida-san,

    I will forward your request to our product expert on this part.

    Thanks,

    Abhinav.

  • Hi Ryuuichi,

    you entirely misuse the REF3430 with this voltage divider! The 4-wire Kelvin connections are designed to correct for voltages in the millivolt range due to voltage drops across fractions of an Ohm. See section 10.2.2.2 of datasheet:

    Your circuit with the heavy voltage divider will definitely not work and that's the reason why the model produces an erratic result.

    Kai

  • Hello,

    I have already confirmed this section.

     I understand that IR drop approximate "mV" is just case on PCB, not specification of REF34XX.

    Actually, there is no spec which is described about potential difference b/w OUT_F and OUT_S in datasheet.

    So, we tried to simulation on this case.

    We expected that OUT_F will saturate arround input voltage due to protection circuit. However, in fact, OUT_F show beyond Input voltage.

    So, we suspect this model lack function of something.

    So again, could you please re-confirm about this ?

    Best Regards,

  • The REF34 model OUT_F upper limit was not part of the model since it is assumed it is a mV and not such a large voltage. The model also assumes it is going to be a typical ADC voltage reference and it was not designed for this type of system.

    The REF34 model is also behavioral and not structural so it will not cover every use case.