Unpowered IO protection i.MX8M Nano

[JHT]

Hello - We are developing an application using the i.X8M Nano.  Do we need to prevent the I/O from being driven when unpowered.  If USB VBUS and DP/DN are driven when the i.MX8m Nano is unpowered is this an issue?  Thank you.

[JHT]

Thank you so much for the quick reply.  Is that also true for the USB D+/D- and VBUS? 

[riteshmpatel · Accepted solution]

Hi @JHT,

I hope you are doing well.

It is recommended to not drive I/O pins externally while the I/O power supply for the pin (NVCC_xxx) is OFF. This can cause internal latch-up and malfunctions due to reverse current flows.

Thanks & Regards,
Ritesh M Patel

[JHT]

Thank you so much for the quick reply.  One follow-on - this applies to USB as well.  I am asking because this case that requires high-BW switches ect and it seems like a case where the part should be able to handle this as for any USB based power delivery system its difficult to guarantee that an undisciplined port will not be accessing D+/D-.