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TLV3402: About output when there is no input.

Kengo.Y
Guru 10385 points
Part Number: TLV3402

Hi team,

I checked the operation for TLV3402.
Is this a normal waveform?
It drops to Low momentarily.

Ch1:VCC Ch2:1IN- Ch3:1IN+ Ch4:1OUT


What is the output of TLV3402 when there is no input?

Sincerely.
Kengo.

  • 0
    TI__Mastermind 23425 points

    Kengo

    Thanks for your interest in the nanopower TLV3402.  

    It is hard for me to determine what is causing that momentary dip without a more zoomed in picture of the two inputs at that moment.  How far apart are voltages being applied to the inputs.  Again, I can't really tell at 1V/division.  If the comparator inputs are very close in voltage, it is possible that you have some minor coupling from the output to the inputs that causes the comparator to see a logic low input momentarily.  I would suggest implementing some external hysteresis if the inputs are close in voltage or their is noise in the system.  I just would need more information about the inputs in order to give a more detailed analysis.  Also, please make sure you are using a bypass capacitor for your power supplies.  This comparator may be a low power device, but the output still transitions quickly when it changes states and this can cause spikes on your supply line if not properly bypassed.

    Chuck

  • 0 in reply to Chuck Sins
    Guru 10385 points

    Chuck,

    Thank you for your reply.
    I'll check in more detail.

    By the way, what is the output of TLV3402 when there is no input?
    Hi-Z?

    Ch1:VCC Ch2:1IN- Ch3:1IN+ Ch4:1OUT


    Is this a normal operation?

    Sincerely.
    Kengo.

  • +1 in reply to Kengo.Y
    Guru 140200 points

    Hi Kengo,

    what do you mean by "no input"? Nothing connected to the inputs and by this the inputs floating? Or input voltages zero?

    Please show a schematic. And explain in detail what is going on during power-up.

    Kai

  • +1 in reply to kai klaas69
    TI__Mastermind 23425 points

    Sorry Kengo

    would be best to show the schematic as Kai suggested but to answer your question, if by no input you mean the inputs to the comparator are floating, that is not a normal test condition.  If the comparator is powered and the inputs are floating, it is hard to predict the output condition since the inputs can be at any possible value due to circuit loading or device parasitics.

    Chuck