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LP55231: Is it permissable to run the I/O voltage of the LP55231 at 3.6V if VDD is connected to 3.4V

UA&A_CodyDowling
Intellectual 875 points
Part Number: LP55231

Our LP55231 is running from a traditional 3.3V rail. However, the microcontroller that provides I2C communication to the LP55231 (and is connected to INT and EN) must be powered by 3.6VDC rail.  (I know- it's strange, but there are some valid reasons that we don't have control over at the moment.) We were looking at bus translators, but I thought I would ask if they were even required first.

I do see that max recommended SCL/SDA voltage in the data sheet is VDD, but it seems all of the pins can handle 5VDC. Should we expect any abnormalities if we run the device this way? My concern is that there may be internal ESD structures (or otherwise) attached to those pins and that, by running those pins at 3.6VDC, we might forward bias those. Is that a legitimate concern?

Would changing the rail voltage of the LP55231 to something more like 3.4 or 3.5V assuage those concerns?

Thanks in advance for your help,
Cody

  • 0
    TI__Genius 12915 points

    Hi Cody,

    It is not recommended to set voltage of logic pins above VDD. We only validated the recommended operating conditions in datasheet to guarantee IC work normally. So I cannot tell if there is any potential risk by setting SCL/SDA above VDD. I think you can also set VDD to 3.6V rail.