This TAJS225K006RNJ is a 2.2 µF tantalum capacitor rated at 6.3 V DC. The ±10% tolerance means the actual capacitance at 25°C sits between 1.98 µF and 2.42 µF — enough margin for decoupling and filtering where the nominal value isn't critical, but tight enough for timing circuits that rely on RC constants.
The 1206 molded case handles the thermal cycling without cracking the dielectric — a known failure mode in larger case sizes.
ESR and its impact on circuit design
The 18 Ohm ESR is on the high side for a tantalum of this capacitance. At 2.2 µF and 6.3 V, that ESR limits the ripple current handling to roughly 50 mA RMS before self-heating becomes a concern. Pair it with a ceramic 0.1 µF in parallel to shave the high-frequency impedance.
This is a standard-production part suitable for new designs.