6.8 µF at 20 V — bulk decoupling for 12 V rails
The TAJB685K020RNJ is a molded tantalum capacitor from the KYOCERA AVX TAJ series, rated 6.8 µF ±10% at 20 V DC. That 20 V rating gives 33 % derating on a 12 V bus — enough margin to survive the 16 V transients common in 12 V systems without voltage derating concerns. The B case (1411 / 3528 Metric) footprint is a standard 3.50 mm × 2.80 mm × 2.10 mm max height — it fits the same pad layout as other B-case tantalums, so a BOM swap to a different brand or CV product doesn't force a board spin.
The 2.5 Ohm ESR at 20 V / 6.8 µF is typical for a B-case tantalum at this CV product — it limits ripple current handling, suitable for output filtering on a low-power DC-DC converter.