Why the 35 V rating and 4.2 Ohm ESR matter for your rail
The TAJB225M035RNJ: At 35 V rated voltage and 4.2 Ohm ESR, the self-heating from ripple current is the limiting factor — not the voltage headroom. For a 2.2 µF cap on a 24 V rail, the 11 V margin is generous, but the ESR sets the ripple current ceiling at roughly 180 mA RMS before the internal temperature rise exceeds 10 °C.
B case size — footprint and board fit
The B case (EIA 3528-21 / 1210) measures 3.50 mm x 2.80 mm with a seated height of 2.10 mm max. The ±20 % tolerance on 2.2 µF is the wide band — typical for tantalum; if your decoupling budget needs tighter tolerance, plan for a screening step or a higher-grade series.