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SN74AHC1G02: Operation with only 1.8V - long term stability?

Art Mecina
Genius 16655 points
Part Number: SN74AHC1G02

Hello Guys,

Good day.

Our customer is using a SN74AHC1G02 NOR-gate as an inverter, but due to an oversight on my their part they're powering the gate with only 1.8V, not >2.0V as required by the datasheet.

The circuit works fine, even during climatic tests with temperatures between -40°C and +80°C.

On their board the gate is used to control a multiplexer with an external signal. During normal operation the signal is not used (inputs low, output high).

They have to deliver the first batch to their customer with this NOR-gate and they're a bit concerned about the long-term effect.

Do you have any idea what effect ageing will have? Is it likely that the gate will stop behaving correctly, even with the reduced voltage, in the near future?

Thank you for any feedback you can provide on this.

Thanks and regards,

Art

  • +1
    TI__Guru* 97046 points

    Hi Art,

    Since we haven't characterized the device for 1.65V to 1.95V range, I can't say if, how, or when operating there could cause problems. I should say that we don't guarantee that it will work at all in this voltage range, so there's zero guarantees in regards to functionality, DC characteristics, or switching characteristics when operating with a 1.8V supply.

    That being said -- if it works today, there's no reason to expect that it will change over the lifetime of the device with such a low voltage and long channel device. The bigger concern I would have is with future lots of devices possibly not working under all conditions, since we didn't design/characterize the device for this operating range.

    From a reliability standpoint though, this is well within the absolute maximum ratings of the device, and it's even below the normal operating voltages, so I believe that it would still be covered under our reliability testing -- usually we test at the worst case (high temps and high voltages) to cover all lesser values. Reducing the operating voltage will generally extend the lifetime of the device -- although with logic, that's not saying much (since the expected lifetime is already so long).