22 µF, 25 V tantalum — the bulk decoupling sweet spot
The TAJC226K025SNJ: This is a 22 µF, 25 V molded tantalum capacitor in the TAJ series from KYOCERA AVX, tolerance ±10%. The 22 µF at 25 V lands in the most commonly specified range for bulk decoupling on 3.3 V and 5 V rails — enough capacitance to handle transient load steps without oversizing the board footprint.
ESR and thermal budget at 100 kHz
ESR is 1.4 Ohm at 100 kHz — this is the number that sets the ripple current rating and the self-heating inside the can. On a 100 kHz switching rail, a 1.4 Ohm ESR means the capacitor dissipates more heat than a low-ESR polymer; check the board-level thermal margin if the ambient runs above 85 °C.