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LM5164-Q1: Shutdown and Enable Thresholds

Cameron Muldoweny
Prodigy 10 points
Part Number: LM5164-Q1

Tool/software:

Hello,

As I read the datasheet, it appears to me that the chip will enter standby mode when the voltage at EN/UVLO pin falls below 1.4V +0.04V/-0.05V (referencing V_EN-FALLING in the Electrical Characteristics table in section 5.5). By the same logic, I have reason to believe the part will exit standby mode and enable when the voltage at the EN/UVLO pin raises above 1.5V +/- 0.05V (referencing V_EN-RISING). I anticipate my understanding is wrong, as it would suggest there is a possibility the part could enter standby mode as the EN/UVLO voltage lowers to 1.44V and could enable again quickly if there was enough noise on the signal to raise the voltage back up to 1.45V.

Please clarify how these EN/ULVO rising and falling parameters should be interpreted. As I understand it now, there is not enough hysteresis on the EN (standby) thresholds.

Thank you.

  • 0
    TI__Mastermind 40040 points

    Hello Cameron,

    I would look at the typical values, and not min and max values.  If you look at the typ values.  the device will start switching at 1.5V and will stop switching at 1.4V.  Ofcoure there are worse case conditions, but these will not be in opposition to each other but raise and fall togeter as min and max values.  Hope this makes sense.

    David.

  • 0 in reply to David Baba
    Prodigy 10 points

    Ok. Thank you for your answer. Generally, I assume parameter max/mins are independent of each other. Is this something typical for TI to have the worst-case threshold values be in tandem with each other as you described? I would like to avoid having to reach out for support if I see something similar in the future.

  • +1 in reply to Cameron Muldoweny
    TI__Mastermind 40040 points

    Hello Cameron,

    the reason why I am saying they are dependent is because the comparator is using a reference and the MIN, TYP and MAX values are derived from the same reference and its drift with temperature etc... 

    Hope this makes sense.

    David.