Can SNVS_VDD_IN be powered off the 3.3V rail when not using a battery?

[benjaminblanton]

We have eliminated the coin cell battery and would like to power SNVS_VDD_IN off the same 3.3V (with a schottky diode to get to 3.0V) as the 3.3V NVCC_XXX I/O.  We will not have the 2ms delay as the datasheet states.  Will this cause any issues?

[igorpadykov]

Hi Benjamin

SNVS_VDD_IN can be powered by 3.3V  according to Table 9. Operating ranges

i.MX7D Datasheet:

http://cache.nxp.com/files/32bit/doc/data_sheet/IMX7DCEC.pdf 

However as stated in sect.4.1.9 Power-up sequence:

VDD_SNVS_IN to be turned on before any other power supply.

Best regards
igor
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[benjaminblanton]

I found this in the Hardware Development Guide:

If you are driving VDD_SNVS_IN with a non-battery power source, it must be at the same level as VDD_IP8_IN or current will flow between them. When VDD_SNVS_IN is not powered by a battery, it is recommended that VDD_SNVS_IN = VDD_IP8_IN.

So since I am not using a battery, should VDD_SNVS_IN be set to 1.8V?