What this 0.1 µF tantalum cap is for
The TAJR104K020RNJ is a molded tantalum capacitor from the TAJ series, rated 0.1 µF at 20 V with ±10% tolerance. The 0805 case size (2.05 mm × 1.30 mm footprint) suits compact surface-mount layouts where a stable, low-leakage decoupling cap is needed across -55°C to 125°C.
ESR and temperature range — fit for harsh environments
With 25 Ohm ESR at 100 kHz, this cap has higher series resistance than a ceramic of the same value — expect more self-heating under ripple current, so derate for AC loads.
The TAJ series is a long-running standard; second-source equivalents exist from other tantalum manufacturers but pin-compatible drop-in is case-size dependent — confirm the 0805 footprint matches your BOM.