The TAJD685K035RNJ is a 6.8 µF molded tantalum capacitor from the KYOCERA AVX TAJ series, rated at 35 V with ±10% tolerance. In a 2917 (7343 Metric) surface-mount package, it fits a standard bulk decoupling footprint for power rails where the applied voltage stays at 50 % or less of the rated voltage — a common derating rule for solid tantalum. On a 12 V rail, the 35 V rating provides a 2.9× margin; on a 24 V rail, the margin is 1.46×, still within the typical 50 % derating guideline for MnO₂ tantalum.
1.3 Ohm ESR and the ripple current budget
For a 6.8 µF capacitor on a 500 kHz buck converter output, the ripple current is typically a few hundred mA — the 1.3 Ohm ESR keeps the internal temperature rise below 10 °C at 200 mA RMS. If the ripple current exceeds 300 mA RMS, the ESR-driven I²R loss pushes the core temperature above the 125 °C ceiling, so the application should stay within the ripple current rating derived from the ESR and the maximum power dissipation.