STM32U595 showing high current consumption in shutdown mode at low temperature
I have the STM32U595QJI6 installed on a custom PCB sharing its VDD supply line with other components, when the PCB is to go into standby, the command HAL_PWREx_EnterSHUTDOWNMode() is used to put the STM32U595QJI6 into shutdown mode.
The PCBs standby current is as expected, however, when the VDD supply line is at 3.3V, and the STM32U595QJI6 gets colder (locally cooling just the STM32U595QJI6 to 0℃) the standby current starts to increase roughly 3 times higher.
When the VDD supply line is at 3V, this does not occur, and the standby current decreases as the temperature decreases as expected.
When the PCB is running, the running current also decreases when it is cooled to 0℃ as expected, regardless of if the VDD supply line is 3V or 3.3V
All the pins are in an analog state, except the PWR_PUCRx and PWR_PDCRx , which are in a default state.
What could be the cause of this current increase in shutdown mode, under the specific conditions of a 3.3V VDD supply line, and a temperature decrease to 0℃？
It has been confirmed across multiple PCBs using the same circuitry, so it is not the result of an individual PCB error.
