47 µF, 6.3 V, 1.6 Ohm ESR — what the ratings mean on the board
The TAJC476M006Y: This is a standard molded tantalum capacitor from the TAJ series, 47 µF at 6.3 V with ±20 % tolerance. The 1.6 Ohm ESR is the dominant loss term at switching frequencies — at 100 kHz the ripple current heats the part, so the actual ripple current rating is set by the ESR and the case thermal impedance, not the capacitance alone. For a 6.3 V rail with 100 mV ripple, the ripple current is about 62 mA; the self-heating from 1.6 Ohm ESR is roughly 6 mW, negligible in still air but worth checking if the cap sits near a hot regulator. Case code C (2312 / 6032 Metric) measures 6.00 mm x 3.20 mm with a seated height of 2.80 mm max — a common footprint that fits standard pick-and-place reels. The molded body has clear polarity marking, and the flat top makes vacuum pickup reliable.
In an avionics PSU that sees -40 °C cold soak and +105 °C under full load, the cap stays within its derated voltage envelope — at 125 °C the rated voltage is typically derated to 2/3 of the 6.3 V rating, so the working voltage should not exceed 4.2 V at the high end. The same range suits downhole tools and satellite secondary rails where the ambient cycles wide.