9.5 Ohm ESR sets the ripple-current ceiling
The TAJA474M050RNJ: The 9.5 Ohm ESR is the dominant loss term in this 0.47 µF tantalum. At 50 V and 100 kHz, the ripple current that produces a 10 °C self-heat is roughly 70 mA RMS — above that, the internal temperature rise accelerates wear-out. For a decoupling cap on a 48 V bus, the ripple current from the switching converter's inductor ripple is the number to check against this ceiling.
The 1206 case keeps the footprint small, but the 1.80 mm seated height must clear any enclosure lid or conformal-coat thickness.