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Original question:

LM46002-Q1: Behavior if input voltage drops below output voltage

LM46002-Q1: Will this device be damaged if the EN PIN is 12V but the VIN is off.

Jack Li
Intellectual 2380 points
Part Number: LM46002-Q1

Tool/software:

Hi Expert,

My customer  are evaluating LM46002-Q1, the input voltage is 24V and convert output is 12V. Besides, they use another one 12V for enable PIN. However, we notice that the EN PIN input voltage need to be below VIN in Datasheet, they have some concerns if this device will be damaged if the EN PIN is 12V but the VIN is off. Please help to check and give some suggestions, thanks.

Best Regards,

Jack Li

  • 0
    TI__Mastermind 31185 points

    Hello Jack,

    Yes, there will be a possibility of damage or loss of functionality when the device is operated beyond its recommend operating conditions. Please modify the sequencing such that the voltage supplying the EN pin is turned off before disabling the input voltage. 

    Thanks,

    Richard

  • 0 in reply to Richard Fu22
    TI__Intellectual 2380 points

    Hi Richard,

    If my customer still want to use this application., can we add two high-resistance resistor at the EN PIN to avoid this damaged issue, thanks.

    Best Regards,

    Jack Li

  • 0 in reply to Jack Li
    TI__Mastermind 31185 points

    Hi Jack,

    No, that would not be a good solution. The best way to do so is to disable the 12V power supply to the EN pin before turning off the 24V input. The easiest way to disable/enable the device with the 24V input is to just tie the EN pin to VIN so the device can self-start when VIN goes high. 

    Thanks,

    Richard