6.8 µF, 10 V, 4 Ohm ESR — the ripple current ceiling
The TAJS685M010RNJ: This is a molded tantalum capacitor from the TAJ series, 6.8 µF at 10 V with ±20% tolerance. The 4 Ohm ESR is the dominant loss term — it sets the ripple current the part can handle before self-heating pushes the core temperature above the 125 °C limit. For a 10 V rail with 100 mV ripple, the RMS ripple current is roughly 25 mA; the ESR dissipation at that level is under 2.5 mW, well within the package's thermal budget.
Active production — no redesign pressure
The product status is Active.
1206 case, S code — footprint and layout
The 1206 (3216 Metric) case measures 3.20 mm x 1.60 mm with a seated height of 1.20 mm max. The manufacturer size code is S. Surface-mount reflow profile follows standard tantalum recommendations — peak temperature 260 °C, ramp rate below 3 °C/s to avoid thermal shock to the manganese dioxide cathode layer.