32F413: Can I Remove Power from VDDA Pin During Shutdown?

[JOlso.12]

I am chasing reason the for last 4 mA of current that my 32F413 microcontroller draws during low current shutdown.

By "shutdown" I mean sleep mode where my system is powered from a small battery with short life.

A really good engineer would have equipped all ICs on his PCB with 0603 jumpers on their VDD lines so he could actually measure these chips' power consumption during shutdown. However, I failed to do this so I must intuit where this phantom 4mA current is coming from.

On a 32F413 does the VDDA pin draw current during shutdown?

I power my VDDA pin from a heavily-filtered version of VDD. Can I eliminate the VDDA pin's consumption from consideration by removing VDD from it during shutdown, or would this have undesirable consequences?

Any other pins on the 32F413 that unexpectedly suck current during shutdown that might have escaped my review?

Thanks in advance for your suggestions on this.

Jim in Indianapolis US.

[TDK]

VDDA must be connected to VDD. If you're powering solely from VBAT, then yes you can remove both VDD and VDDA, but they need to be tied, per the datasheet.

I would use a thermal camera to look for hot spots. 4mA is enough that you should be able to see it. Could easily be something external to the chip such as a pulldown/pullup or LED. Could be a peripheral was still running, depending on the low power mode you're using.