Molded tantalum for wide-temperature decoupling
The TAJS225M010SNJ is a 2.2 µF, 10 V molded tantalum capacitor from the TAJ series, in a 1206 (3216 Metric) surface-mount package. The 12 Ohm ESR is the headline parameter for a tantalum: it governs the ripple current the part can handle before self-heating shifts the capacitance.
Derating and ESR budget
Tantalum capacitors require voltage derating: a 10 V rated part should see no more than 50-60% of rated voltage in continuous service, so 5-6 V DC bias is the practical ceiling. The ±20% tolerance is standard for tantalum electrolytics — the capacitance at -55°C can drift toward the low end of the band, so a 2.2 µF part may measure 1.76 µF at cold. If the downstream circuit (e.g., an RC time constant or a hold-up cap) needs a tighter window, a ±10% tantalum or a ceramic alternative should be considered.