Why the 10 V rating matters for your rail
The TAJA225M010SNJ: This is a 2.2 µF molded tantalum capacitor rated at 10 V in a 1206 case — the voltage rating is the first thing to check because tantalum capacitors have no surge margin above rated voltage. Derate to 50-60% of rated voltage for reliable operation; on a 5 V rail, this part has comfortable margin.
Lifetime at temperature — the 125°C endurance test
At lower operating temperatures the lifetime extends significantly — the Arrhenius acceleration factor roughly doubles the life for every 10°C drop. For a 85°C ambient, expect well over 10,000 hours of reliable operation.
ESR and ripple current — what the 7 ohm spec means
For a 2.2 µF capacitor, the maximum ripple current is roughly sqrt(ΔT / ESR) where ΔT is the allowed self-heating — typically 2-3°C.