I use two 10uF, 20VDC tantalum capacitors in parallel as decoupling capacitors just after the battery connector. At the moment the battery is plugged in, one of the capacitors sometimes burns out (not always, about 1%).
I measured the surge current of the capacitor when it is powered on by the battery, and it is up to 4A as the following screenshot shows.
I guess the surge current may be the reason for the burning out, but I cannot find any data about the maximum surge current the capacitor can withstand.
The questions are:
How to estimate the power-on surge current of a capacitor? If its ESR is 5ohm and the maximum battery voltage is 8.4V, then the surge current is 8.4/5 = 1.68A? Then how can I know if the capacitor can withstand that?
There is a "maximum allowable ripple current" parameter from the datasheet. It's a smaller value, such as 122mA at 25 degrees celsius, 100kHz. When should I refer to this parameter and promise not to make the current exceed it?
If the surge current is the reason for the failure, how should I choose a tantalum replacement?