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SN74ALVC14: SN74ALVC14DR

Murari Divya
Prodigy 40 points
Part Number: SN74ALVC14
Other Parts Discussed in Thread: SN74LVC3G34

Dear Team,

My self  Murari Divya from Medha Servo Drives pvt.ltd, Hyderabad.

We are using SN74ALVC14 - HEX SCHMITT-TRIGGER INVERTER in our application. It having total 6 inverters but we are using only 4 inverters remaining 2 are not using.

In datasheet it was mentioned that "All unused inputs of the device must be held at VCC or GND to ensure proper device operation."

We are grounded the unused input pins but still we facing problem in our application and it was getting okay when we are ground the unused output pins also.

Please check and tell me the recommendation circuit. Reasons for this kind of problems like noise or mat be floating voltage.

  • 0
    Guru 259920 points

    Unused outputs can be left open

    Please show the schematic. What problems did you see? Can you show an oscilloscope trace?

  • 0 in reply to Clemens Ladisch
    Prodigy 40 points

    Thanks for your reply.

    Attached the schematic for your reference.

    In our application some times/cases problem was coming, but in passive and active mode no difference observed.

    When we are connecting the unused pins to GND, then our application was working normally.

    Kindly check and suggest me..

  • 0 in reply to Murari Divya
    Guru 259920 points

    The schematic looks OK.

    When you have grounded the inverters' inputs, they try to drive their outputs high. So forcing their outputs low will generate a short, and the resulting current can damage them. I do not understand why this would actually improve the behaviour.

    Can you describe in more detail what the problem with the inverters' output signals is? Please show an oscilloscope trace; it is not possible to help you without it.

    (The simplest way to get three buffered outputs would be the SN74LVC3G34.)