Molded tantalum for tight boards
The TAJB335M016RNJ is a molded tantalum capacitor from the KYOCERA AVX TAJ series, rated at 3.3 µF with ±20% tolerance and a 16 V voltage rating. Its B case size (1411 / 3528 Metric) fits standard surface-mount pads, and the 4.5 Ohm ESR sets the ripple current ceiling for decoupling or bulk storage on a 12 V or 5 V rail.
ESR and derating for the BOM
At 4.5 Ohm ESR, this capacitor dissipates heat proportional to the ripple current squared. For a 100 kHz buck converter output, the ripple current should stay below the capacitor's rated ripple limit to keep self-heating under 10°C — check the application note for the specific frequency derating. The 16 V rating allows a standard 50% derating on a 5 V rail (8 V margin) or 30% on a 12 V rail (4.8 V margin), which is conservative for tantalum reliability. Running at 80% of rated voltage (12.8 V) is not recommended for long-life designs.