3.3 µF at 25 V — the bulk decoupling ceiling on a 1206 footprint
The TAJA335M025RNJ is a molded tantalum capacitor from the KYOCERA AVX TAJ series, delivering 3.3 µF capacitance with a ±20 % tolerance at a rated voltage of 25 V. For a 3.3 V rail decoupling a 100 mA transient, the voltage drop across the ESR is 0.37 V, which is within the typical regulator headroom but eats into the noise margin.
The 3.7 Ohm ESR is specified at 25 °C; at 125 °C the ESR roughly doubles, so the ripple current rating must be derated by the square root of the temperature factor. A 20 % voltage derating (20 V max applied on a 25 V part) is standard practice for tantalum capacitors at the high end of the temperature range to avoid field-failure from surge current.
Active lifecycle — no LTB window to plan around
1206 case — the board-space trade-off
The 1206 (3216 Metric) case measures 3.20 mm x 1.60 mm with a seated height of 1.80 mm. The land pattern follows the standard IPC-7351 footprint for 1206 chip capacitors — no via-in-pad required, but the pad width should match the terminal width to avoid solder bridging. The molded body is polarity-sensitive; the anode terminal is marked with a stripe on the top face.