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TPUL2T323: Time setting inquiry

Will Wang47
Expert 8710 points

Part Number: TPUL2T323

Hi  team,

Customer is evaluating TPUL2T323 to generate >13s pulse.

They find in datasheet 150kohm + 100nF get 14.3s workable for them.

While when using the excel tool do the calculation, they find the nominal value change to 13.78s;

Based on the datasheet figure 5-15, the K value is ~0.9, so excel table looks right, since they get close K figure.

We don't know why the table 5-1 value don't match excel value, could you help check this?

If customer want a good fit >13s but close to it, what's your recommended RC combination?

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Regards,

Will

  • 0
    TI__Mastermind 33395 points

    Hi will,

    150kOhms and 100nF or a little less like around ~90nF seems fine.

    The datasheet table data is from bench testing and the excel data is from simulation, so the datasheet table should be a little more accurate on average. 

    Remember that the output pulses have 10% margin of error, so calculating an output pulse width of 13s and getting 14.2s is also to be expected.

    Best,

    Malcolm

  • 0 in reply to Malcolm Lyn
    TI__Expert 8710 points

    Hi Malcolm,

    Thanks for your feedback.

    Do you mean that the table 5-1 is bench testing result?

    If that's the case, excel calculation get the range of the time, and we just make sure the value min and max meet customer requirement, then that's OK, does my understanding correct?

    Regards,

    Will

  • 0 in reply to Will Wang47
    TI__Mastermind 33395 points

    Hi Will,

    Yes, table 5-1 is comprised of bench test results.

    Yes, I think your understanding is correct. Just understand with whatever time you design for there is a +/- 10% error. The customer needs to be ok with 10% margin of error.

    Best,

    Malcolm