SN74LVC2G07: out of input transition rise rate

Part Number: SN74LVC2G07
Other Parts Discussed in Thread: SN74LVC2G17

Hi sir,

My customer is using SN74LVC2G07DCKR, the input signal is 33.6us/1.2V = 28000ns/V.

This is out of our datasheet recommendation (max 10ns/V), will it produce any potential risk?

If there will be potential risk, do we have other part without the timing requirement and pin to pin with SN74LVC2G07DCKR?

Thank you.

  • Hello,

    The issues with slow inputs are explained in this FAQ: How does a slow or floating input affect a CMOS device? 

    The short answer is - yes, this presents a risk of reduction in reliabilty and possibly oscillatory outputs. Typically with an open-drain device, the oscillations at the output are not visible because the output transitions are so slow. In this case, the only issue is reduction in reliability. We don't have any data that shows how much this will affect reliability, so I don't have any way to predict a failure rate or time.

    the input signal is 33.6us/1.2V = 28000ns/V.

    Before I present solutions -- can you verify if they are operating the device at 1.2V? The LVC family only supports 1.65V to 5.5V operation.

    Do we have a schematic and/or scope shots of operation?

  • Hi Emrys,

    SN74LVC2G07DCKR VCC pin and input signal are 3.3V level.

    Not sure if we have pin to pin part, open-drain output but with Schmitt-trigger input 2-ch buffer?

    I checked and seems we only have push-pull output SN74LVC2G17DCKR?

    Thank you.

  • I checked and seems we only have push-pull output SN74LVC2G17DCKR?

    That is correct - there isn't a pin-to-pin solution that will solve the issue.

    The best solution is to add a Schmitt-trigger buffer at the inputs of the device. The SN74LVC2G17 is a good choice.