I've got a couple devices using MKL26Z128VFM4s that have failed in a way that causes the uC to repeatably draw very large (>1A, given enough power supply) currents as soon as power is supplied. I don't know what events might have preceded the initial failure (they were out of my hands at the time), but I had two suspicions: floating inputs and a weak overvoltage on an input pin. The input overvoltage was limited to VCC+0.9V and could only have supplied about 50uA, and applying the same conditions to other devices for extended durations has not replicated the failure. There are also a couple unused pins, and I don't know what could have been going on with those. When the first one happened, I suspected ESD, but then a second one came back to my bench with similar symptoms so I expect it's something more deterministic.
Does anybody know what sort of conditions might damage a chip like that? I did find that if I supply enough power, in the brief moment before it gets dangerously hot, at least one of the KL26s still executes its code and responds to SWD.
Hi, Brain,
Regarding the failure of the Kl26, it is difficult to give the concrete cause, I only give you some clue. If you input over-voltage on the input pin of analog or digital pins, you should connect a serial resistor so that the input current is limited less than 2mA. but I do not think the over_voltage on the input pin can leads to the failure of the processor, pls check the power supply pins, each power supply pins should be connect a 0.1uF capacitor.
If possible, you can contact local FAE to do failure analysis to track the cause.
BR
XiangJun Rong