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MCU dead after connecting 5v to a USB data line #233

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ADVecu opened this issue Feb 20, 2024 · 0 comments
Open

MCU dead after connecting 5v to a USB data line #233

ADVecu opened this issue Feb 20, 2024 · 0 comments

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@ADVecu
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ADVecu commented Feb 20, 2024

By mistake I connected an external USB port and it turns out that through one of the data lines I connected the 5v of the USB port, the result, the MCU was dead.

MRE R0.6.0 Assembled by JLCPCB
STM32F427VGT6
TLE8888 and TC4427Assembled with hot air station
AV9 as output
AV8 Analog
VR
GP5 - GP6 12v

Removed:
R19
R17
R18
R15
R53
R85
R86
R84

This is the USB port that I am connecting, I have already tested it with more boards and it works perfectly

STM32F4usb2

The exact connection that was made was the following:

USB GND -> Pin 17 - H4
USB 5V -> Pin 16 - J1
USB D- -> Pin 15 - J2
USB D+ -> Pin 19 - H2

The 12v power supply was normally connected, no additional sensor was connected.

After correcting the error it no longer reacted to the USB connection, when disassembling I found that between TP3 and TP0 (3.3V and ground) it was shorted, the TLE8888 and the MCU were very hot, and it was consuming 950 mA from the power supply at 13 volts

According to what I could see in the datasheet, pins PA11 and PA12 are 5V tolerant, but I could be wrong.

STM32F4PINS
STM32F4FT

If it is not tolerant to 5v, should D16 be replaced with one at 3.3v?
I am probably saying something stupid

STM32F4usb

After changing the MCU, everything was resolved, except that U31 smoked when connected to 12v again. It may be related or not, I will open another issue with this detail

Any clarification or additional information please let me know.

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