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STM32F303RBT6 - Bad Analog Section

Question asked by Canada Rob on Apr 18, 2016
Latest reply on Apr 19, 2016 by Clive One
I had previously received the following response on this question from this forum...

This is not a known issue and the part has been shipped and used in this manner already in K units without any returns

Use the standard sales channel RMA process and the process will analyse the part for damage and determine if it was an issue with silicon or external cct

The customer has responded with the following commentary...

I had a look at this failed unit last week. To re-cap, the unit appeared to operate as expected during one series of tests (low power) but failed during a functional (high power test). 

 

What I found was that the MCU had been damaged and drew significantly more current then expected (Power draw when injecting directly onto our 3.3 Volt rail is typically 15mA and this unit draws closer to 75mA). This excess current changes the we detect system power resulting the odd behaviour in the functional test.

 

 This was the only failure of it’s kind in a 3k piece pilot build.

 

Ideally, I’d like to know exactly why the unit failed but I’m happy to call it a “one-off” occurrence. 

 

 Question, the SWD lines as well as the RESET line are exposed on a header. If these pins were subjected to a high external voltage (12 or 24 Volts), could they result in the excess current draw but maybe not affect general functionality?

Rob Wilson - this does sound like a one off customer error but I wanted to check and make sure we have not seen this elsewhere.

   Appreciate your help.

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