22 µF, 20 V, 1.6 Ohm ESR — bulk decoupling for hot rails
The TAJC226K020HNJ: This 22 µF tantalum capacitor from the TAJ series is rated at 20 V with an ESR of 1.6 Ohm at 100 kHz. The 20 V rating gives 20% derating margin on a 16 V rail, which is standard practice for tantalum to avoid surge failures. The 1.6 Ohm ESR limits ripple current heating and sets the capacitor's filtering effectiveness at switching frequencies — a lower ESR would improve ripple suppression but increase inrush current stress on the supply.
The 2000-hour lifetime at 125°C means the capacitor's electrolyte dry-out accelerates above 85°C — for a 105°C ambient, the expected life is roughly half the 125°C figure per the Arrhenius model. Derate voltage by 50% above 85°C to maintain reliability.