Hello everyone, @Omar_Anguiano
I am facing an issue with the SNVS (Secure Non-Volatile Storage) backup domain current on an i.MX RT1064 (MIMXRT1064CVJ5B) microcontroller and would appreciate your help.
The Core Problem:
The backup battery for the SNVS domain is discharging too quickly. The battery is a CR1220 with a 35mAh capacity.
Measurements & Discrepancy:
The microcontroller is running at 532 MHz.
According to application note AN12245, the expected input current for the SNVS domain should be around 25.7 µA.
However, my measurements show a constant current draw of 38 µA (Note: 38 µA is more than 25.7 µA, indicates something is not configured correctly and the MCU might not be in the expected low-power state).
This 38 µA current remains constant even when the main power supply (VDD_HIGH_IN) is removed.
Crucially, the current remains at 38 µA even when I intentionally place the chip into its SNVS low-power mode. It does not drop to the expected 10µA range.
What I've Already Tried:
I have already disabled the internal switch between VDD_HIGH_IN and SNVS_VDD by setting bit 12 (DISCON_HIGH_SNVS) in the XTALOSC24M_MISC0 register. Despite this, the current draw remains unchanged.
The key questions are:
Why is the SNVS current a constant 38 µA instead of the expected ~25.7 µA in active mode?
Why does this current not decrease when entering SNVS mode, and why is it not in the 10-12 microamp range as expected for a proper backup state?
What could be preventing the chip from entering a true low-power SNVS state?
I am attaching the relevant schematic portion for the power and SNVS section below. Any insight into what I might be missing would be greatly appreciated.


