2025-07-16 5:53 AM - edited 2025-07-16 6:55 AM
Hi,
I have made up six boards and three of them had an unusually high standby current (35mA instead of 1mA).
Eventually, when the IC was removed, we found Pins 5 & 6 of the removed IC were shorted internally (0.3R)
They were also shorted to pin 45 with 3.7R. The other two boards are showing similar shorts.
The board worked fine with a new MCU.
Does anyone know what might cause this short?
TIA,
Patrick.
2025-07-16 6:17 AM
> STM32G070CB76
Not a chip. Probably STM32G070CBT6?
Pins shorted indicates hardware damage. Probably due to overvoltage at one point. Does L3 cause VREF+ to spike at powerup? What is attached to LED_WHITE?
2025-07-16 7:37 AM
Thanks, typo in chip code corrected to STM32G070CBT6.
LED_WHITE connects through a resistor to a led.
VREF+.. I don't know - some kind of intermittent event? These are the second batch of boards - the first 10 had no issues with hundreds/thousands of power-ups.
Could ESD be an issue?
2025-07-16 8:55 AM
Yep, it could be ESD.
2025-07-16 10:25 AM
ESD could always be a cause of a hardware failure, but in my experience it's typically something else. These chips aren't particularly sensitive to ESD.