High-current failure in KL26

brianbezanson — Mon, 19 Oct 2015 18:20:26 GMT

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.

Re: High-current failure in KL26

xiangjun_rong — Wed, 21 Oct 2015 05:34:26 GMT

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.

XiangJun Rong

Kinetis MicrocontrollersのトピックRe: High-current failure in KL26

High-current failure in KL26

Re: High-current failure in KL26