Power decoupling capacitor caused high current consumption

[rozpruwacz]

Hi all,

I want to share with You my issue I had with couple of my battery powered sensor nodes. They are build on atmega328p + RFM69W. They were working perfect for over a year consuming low power. But then, one after other started to consume much more current. It turned out to be a failed power decoupling capacitors. When I replaced them the current consumption went back to normal level. The failed capacitors measured with the ohm meter reported low resistance, like less that 10kOhm or even less that 1kOhm. Has anyone encountered such a problem ? it was three capacitors in three different nodes, so it's like 5% of all capacitors in all my nodes :) It would be bad if I would need to resolder those capacitors every year ...

[Yveaux]

@rozpruwacz are they all from the same batch/order? Brand or China made?

[rozpruwacz]

@yveaux one capacitor was on the bme280 module from aliexpress, but other two are samsung capacitors bought from big european seller (tme.eu).

[lood29]

MLCC or tantalum caps ?

[rozpruwacz]

@lood29 MLCC

[lood29]

Switch to tantalum if you have space, much better for battery powered as a decoupling cap, low leakage.

Choose a cap with voltage 3x to 4x of input voltage.