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SN54LVC00A: Logic Output

Steven Pavesio
Prodigy 110 points
Part Number: SN54LVC00A


If my Vcc is at 3.3V and I input 5V TTL logic signal, how does this affect the operation of the chip?

  • 0
    TI__Guru 62930 points

    Steven,

    This can be addressed by examining the Absolute Max Ratings.

    The Vi range is listed at 0.5 to 6.5V.   Staying below 6.5V will mean that the reliability of the device will not be impacted.

    From a functional standpoint, the TTL levels of 0.8 and 2V for VOL and VOH are satisfied by the SN54LVC00A VIL/VIH levels of 0.8 and 2V.

    Additionally, the Recommended Operating Conditions show a Vi max of 5.5V to insure all specifications are met. 

    So, if your signal does not exceed 5.5V, then there is no issue.   If it is greater than 5.5V, but less than 6.5V, then it will not damage the device, but some of the timing parameters may no longer be valid.

    If this answers your question, please click "This Resolved My Issue"
    Regards,
    Wade