The TAJS105M010RNJ: This is a 1 µF molded tantalum capacitor from the TAJ series, rated 10 V with ±20% tolerance. The 25 Ohm ESR is the spec that matters for any circuit with AC ripple — at 100 kHz, the self-heating from ripple current through that ESR limits the usable current to roughly 20 mA RMS before the part exceeds its 125°C ceiling.
The TAJ series is a mature, widely second-sourced platform — if a future shortage hits this exact code, a functionally equivalent 1 µF, 10 V, 1206 molded tantalum from another manufacturer (e.g., Kemet T491 series) can be evaluated without a board spin, though the ESR and case size code should be cross-checked.
1206 footprint — the size code S case
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. The 0.047" max height keeps it under most low-profile component keep-outs. Standard reflow profile for tantalum capacitors applies — preheat ramp limited to 3°C/s to avoid thermal shock to the MnO2 dielectric.