2.2 µF at 25 V — the decoupling sweet spot for a 1206 tantalum
This TAJA225K025KNJ is a molded tantalum capacitor from the TAJ series, rated 2.2 µF with ±10% tolerance and a 25 V DC voltage rating.
7 Ohm ESR — the ripple-current constraint at 100 kHz
The equivalent series resistance is 7 Ohm at 100 kHz. For a bulk decoupling cap on a switching regulator output, that ESR sets the ripple voltage and the self-heating. At 100 kHz ripple current, a 7 Ohm ESR means the cap dissipates I² × 7 W — budget the ripple current so the internal temperature rise stays within the 125 °C limit.
