in a new product we use the DA9061-66 with an iMX6ULL. The product is finished and we already had market launch.
Generally everything works fine (passed all EMI tests with above the norm levels without problems, no problems during our development phase) but unfortunately in our long time tests we experience problems. After ~1-21 days on some of our devices we see that the DA9061 shuts off the Buck3 regulator which supplies our DDR3 RAM (we use one 16-Bit DDR3 IC). This leads to a freezing device from which there is no other way out than turning the power off and on again. So market launch is stopped until we resolve the problem.
At the moment we have no idea why it happens.
Here is what we already tried:
- We monitored that there are no telegrams on I2C which shut off the regulator when the device has a failure.
- On a device in failure mode, we read out the registers of the DA9061 with the development board, I will attach the file to this post as .pdf file, but it is a .txt file. We found nothing unusual. Buck3 is enabled. Maybe we overlooked something.
- On this failing device we monitored the current on the Buck 3 rail and there was no overcurrent event.
- Vref of the DA9061 on device in freeze was 1,19V
- Vcore of the DA9061 was 2.5V
- Only disconnecting the power seems to get the DA9061 back to normal work
- It seems totally random when it happens. On one device it happened after 30 minutes, next run after 20 days. Same software, same environment and so on
- We tried to force the error with different approaches but until now we didn't find a way to reproduce it. It only happens completely random, but it seems as if it always happens on the same devices.
- Our system logs (we use Linux) don't show anything. The system just stops without any error message probably when the RAM voltage fails. Until now we didn't get a trigger to the falling voltage, we are still trying to. Its a bit of a problem with the long time between the error occurence.
At the moment the most plausible explanation to us is that the DA9061 chips on this devices are somehow damaged.
We already submitted schematics and layout to Dialog but got no feedback to them now for 24 days, which is very disappointing to me.
Has anyone here ever had a comparable thing with this PMIC or this PMIC family? We are at a dead end here as it seems.
Thank you very much,