15 µF at 4 V — what it fits
The 2 Ohm ESR is the key loss element — at 4 V and 15 µF, the ripple current capability is modest, so it suits low-frequency decoupling or filtering where the AC ripple is small.
The 1.20 mm seated height is low enough to fit under a mezzanine board. Rework with hot air is straightforward — the molded body has no internal seal to crack, and the terminations are tin-plated. The ±20% tolerance is typical for tantalum; if your circuit needs tighter than that, you are looking at a different dielectric.
Active — no LTB pressure
Listed as Active from KYOCERA AVX. The TAJ series is a long-running molded tantalum family, so second-source equivalents exist from other manufacturers — but the exact order code TAJT156M004RNJ is the KYOCERA AVX part. Sourced per RFQ; availability confirmed at quote time.