STM32L073RZ Nucleo board getting VERY hot

[Gordon_01]

Hi Community,

An STM32L073R Nucleo board straight out the packet. Plug in the USB cable and immediately, the L073 gets VERY hot. LD2 is flashing which I presume is an application running in the micro. Have removed the jumper JP6 which supplies the L073 with power and everything remains cool (as we would expect) As soon as I replace the link the micro again, heats up.

The power supply measured at JP6 with the link removed is a good 3.3V. and the board is recognised as a USB drive when connected.

I have an older F401 Nucleo board which works without issue in the same setup.

Any ideas or suggestions?  

[Andrew Neil]

Anything connected to the board ?

Is the board on a non-conductive surface - nothing to short the underside pins ?

[Gordon_01]

Hi Andrew and thanks for your interest.

Nothing connected - straight out the packaging from Mouser. Working on a wooden bench. You can feel it get hot whilst holding it to make the Link JP6. looking under a microscope, I don’t see any shorts or blemishes. 

I do not take special care regarding antistatic precautions but having used other ST Nucleo boards and equivalents from other manufactures, I would not expect static damage.   

My main interest is to ensure that this is not a common fault or mistake in the PCB so that if I buy a replacement, I do not see the same issue...  

[Andrew Neil]

Just contact the seller and describe the fault - they should provide a replacement.

[Gordon_01]

Thanks - will do!

[Peter BENSCH]

In the past, some users complained about similar issues after connecting a NUCLEO to a MAC that apparently was supplying too high a voltage. Are you using a MAC?

[Gordon_01]

Hi Peter,

 

No - I’m using a Dell Windows Desktop. But… the 5V goes through a reg to 3.3V so the actual voltage should not matter (within reason...) or am I missing something.Measured 5V supply is 5.15V. Measured 3.3V is 3.28V with JP6 NOT fitted. Thanks for your interest.

Gordon