High Current on Nucleo H745ZI-Q in Standby Mode

[AlpineTrekker]

Hello all,

I am evaluating the STM32H745 for an application which requires very low power. I am using the Nucleo H745ZI-Q for this evaluation and STM example code I downloaded. The datasheet for the STM32H745 indicates that I should expect to see a current draw in the low hundreds of microamps with both cores in Standby mode. I selected and built an example made for the Nucleo H745ZI-Q called PWR_STANDBY_RTC to test on my board. I am seeing a current draw of approximately 7 mA in standby mode when I measure current draw across VDD MCU at header J5. The example seems to be working as I can see the LEDs light up from both cores and then turn off to indicate they are going into Standby mode. It wakes up after a timeout and draws 70 mA and then goes back into Standby with a 7 mA draw. 

I would appreciate any ideas as to what the problem here might be. Am I misguided in thinking I can get the datasheet Standby current with this dev board?

Example Code:

STM32CubeH7 - STM32Cube MCU Package for STM32H7 series (HAL, Low-Layer APIs and CMSIS, USB, TCP/IP, File system, RTOS, Graphic - and examples running on ST boards) - STMicroelectronics

Nucleo H745ZI-Q (C01) Schematic:

NUCLEO-H745ZI-Q - STM32 Nucleo-144 development board with STM32H745ZI MCU, SMPS, supports Arduino, ST Zio and morpho connectivity - STMicroelectronics

[FBL]

Hello @AlpineTrekker and welcome to ST community,

First, for the schematics of NUCLEO-H745ZI-Q you should refer to MB1363-H745ZIQ-D01 

Could you provide more details about the issue? Do you want to check the testing conditions: 
Flash memory, IWDG, SVOS, unused pins mode being set or not, LDO or SMPS?

You may need to refer to Table 43. and Table 44. for typical and maximum current consumption in Stop guaranteed by ST

Hope this helps!