STM32L4A6QGI6P consistently show current spike after some interval.

[MrVanBa]

Hello everyone,

I'm currently working with a custom STM32L4A6QGI6P microcontroller and aiming to achieve consistent current consumption during runtime for a measurement test. However, I consistently encounter a current spike after a short interval, precisely every 33ms.

I've attempted various solutions, including pulling down every in-use GPIO. I've even gone as far as erasing the firmware for testing purposes. Despite these efforts, the current spike persists.

Could you please help me understand the cause of this behavior and suggest potential fixes?

Your assistance is greatly appreciated.

Additionally, I've attached the current consumption graph captured during testing for your reference.

Thank you in advance.

[Danish1]

That is a huge current spike. What other components do you have on your pcb, and how have you excluded them from being the source of the current spike?

The "P" variant has a different pin-out which brings out pins for an external switch-mode power-supply to feed the core between 1.0 and 1.2V. It cannot be swapped with the non-P version as that has a different pinout. (Most likely you're aware of this, but I made that mistake once).

I assume you have on your circuit board. I assume you have a switch-mode power-supply to feed the core. You are required to disconnect this power-supply at startup. Is it possible your disconnect circuit isn't working (and the external SMPS is fighting the internal linear regulator)?