The TAJT686K002RNJ is a molded tantalum capacitor from the TAJ series, rated at 68 µF with a 2.5 V working voltage and ±10% tolerance. The 1.5 Ohm ESR sets the ripple current ceiling — for a 100 kHz square wave, the self-heating stays within the 125°C limit only when the RMS ripple current is kept below approximately 400 mA. This part is suited for bulk decoupling on 1.8 V, 1.2 V, or 0.9 V supply rails where the voltage margin is adequate.
At the upper end, the leakage current and ESR both increase; the derating guideline for tantalum capacitors recommends applying a 50% voltage derating above 85°C to maintain reliability.
The molded construction provides mechanical protection and consistent standoff height for reflow soldering.