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I've been working with microwatt and nanowatt power consumption devices for a while and I've mentioned that sometimes, due to unknown reason, current consumption increases in order of magnitude. Currently I've made a few devices that have standby current around few microamps and mentioned this behavior on many chips (some of them: LIS3DH, nRF24L01). I have no idea, maybe it could be some kind of latent electrostatic or thermal damage on chip. The fact is: sometimes chips are getting 10-200 uA increase of current consumption, while still being fully operational. Well, at least before battery goes dead.

Currently I've been just replacing damaged chips with new ones, but now we are increasing amount of devices and such method is no longer appropriate. What is happening and how to avoid this?

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    \$\begingroup\$ I've seen cases where production IC devices will exhibit a sudden shift by about an order of magnitude and then suddenly return to almost exactly the same prior level. The timing of which, for a single device, distributes out into an almost beautifully Gaussian shaped curve -- suggesting Poisson events to me. Working with the manufacturer, we never did resolve the root cause. It was almost spooky how well the current levels were defined, too. As though there were impossible bands separating the achieved ones. You may need to find different devices if my description seems familiar to you. \$\endgroup\$
    – jonk
    Commented Oct 2, 2018 at 19:00

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The 3 big enemies of electronic parts are:

1) Unstable or noisy power supply, already at the devices specified limits.

2) Static charges or creapage current due to high voltage close to high-impedance inputs.

3) Temperature rise of device by ambient rise or a nearby power device or lack of a heat-sink (if required). If shoot-through currents are allowed due to a lack of current limiting then a latent failure with a semi-predictable timeline is inevitable. I have seen small zeners fail and LEDs fail due to large capacitors wired directly across them as a ripple filter. Sometimes an over sized capacitor is NOT a good thing.

Combine with a part that is hotter than expected (heat almost always increases overall current flow, and can create 'weak spots' that allow a shoot-through of higher current) and you have ripe conditions for shoot-through currents which often destroy a device the first time. It does not mean the devices insides have melted into a blob (which is possible) as much as it means there is now a leakage path in the device itself.

If this event repeats the current flow could increase by ten each time, but sooner or later there is a 'last time' when the part no longer functions. It may get very hot and/or read as a short across its power pins.

I did not mention cold because it takes arctic-like conditions for many parts to even drift out of spec. Below 100\$^o\$ F the problem is solder connections cracking due to a shrinking motherboard.

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