2.2 µF, 20 V, 5.3 Ohm ESR — the decoupling fit
The TAJA225K020RNJ: Rated at 2.2 µF and 20 V with a 5.3 Ohm ESR, this TAJ-series molded tantalum sits in the 1206 case. The 20 V rating gives headroom on a 12 V or 5 V rail — you can run it at 80 % derating per MIL-PRF-55365 guidelines and still stay below the voltage limit. The 5.3 Ohm ESR is the number that sets ripple current capability: at 100 kHz, the allowed ripple current is roughly the square root of (power dissipation divided by ESR). For a typical 0.1 W dissipation limit in free air, that works out to about 133 mA RMS — enough for output filtering on a low-power DC-DC converter.
Rework and board-fit notes
Molded 1206 case — 3.20 mm x 1.60 mm footprint, 1.80 mm seated height. The body is solid epoxy, so it takes reflow soldering without cracking if the preheat ramp is controlled.
The capacitance change with temperature is roughly ±10 % over that span — the 2.2 µF nominal value holds within spec at cold soak and under the hood.