VDD_HIGH_IN, VDD_SNVS_IN connection

[jhones]

Hi,

Referring to item #2 in "Table 2-6. Power and decouple recommendations" in the iMX6 hardware development guide:

https://www.nxp.com/docs/en/user-guide/IMX6DQ6SDLHDG.pdf 

"When VDD_HIGH_IN > VDD_SNVS_IN, VDD_HIGH_IN supplies all SNVS domain current and current flows into VDD_SNVS_IN to charge a coin cell battery"

In case of not using a coin-cell and supplying VDD_SNVS_IN pins in IMX6 only from PMIC PMPF0100 VSNVS 3.0V regulator, is it allowed for VDD_HIGH_IN to be fed from a different power supply greater than VDD_SNVS_IN?

In case it is allowed but not recommended can you please explain why?

Thanks for your support.

[gusarambula]

Hello  Aviad H,

VDD_SNVS_IN supply must be turned ON before any other power supply so it’s highly recommended that you connect it to VDD_HIGH_IN if no coin-cell will be used.

You could feed it from a different supply but it’s important that VDD_HIGH_IN is not powered while VDD_SNVS_IN is off and you would need to setup some protection as mentioned on the following thread:

https://community.nxp.com/message/942931

Please also keep in mind the valid voltage range for VDD_HIGH_IN listed on the datasheet.

I hope this helps,

Regards,