The TAJA685M010HNJ is a molded tantalum capacitor from the KYOCERA AVX TAJ series, rated at 6.8 µF with ±20% tolerance and 10 V DC. The 4 Ohm ESR at 100 kHz sets the ripple current ceiling — for a 100 kHz switching supply output, that ESR means about 0.5 A ripple current before self-heating cuts into the 2000-hour life at 125°C.
Temperature endurance and field fit
For a 24/7 outdoor base station running at 85°C ambient, that translates to over 4000 hours before the capacitance drifts outside tolerance. The 10 V rating at 6.8 µF provides a 20% derating margin on a 5 V rail, which is standard practice for tantalum caps to avoid surge failures.