68 µF bulk cap for a 2.5 V rail — what the ratings mean
The TAJT686M002RNJ: This is a 68 µF molded tantalum capacitor rated at 2.5 V with ±20% tolerance — the bulk decoupling choice for a 1.8 V or 2.5 V supply rail where the voltage margin above the rail is tight. The 1.5 Ohm ESR sets the self-heating under ripple current: at 68 µF and 2.5 V, the ripple current capability is modest, so this part suits low-ripple linear post-regulation or a lightly loaded DC-DC output, not a high-ripple switching converter input.