68 µF, 6.3 V — ESR drives the decoupling budget
The TAJB686K006RNJV: This is a 68 µF molded tantalum at 6.3 V with a 900 mOhm ESR measured at 100 kHz. The ESR is the limiting factor for ripple current handling — at 900 mOhm the self-heating at the capacitor's rated ripple current will be significant.
The rated endurance is 2000 hours at 125 °C with full rated voltage applied. That is the accelerated life test condition — in a real design at 85 °C with voltage derated to 80 %, the useful life is substantially longer. The -55 °C low end means this cap can sit on a cold-start power bus without the capacitance drop that plagues aluminum electrolytics. For continuous operation above 105 °C, expect to derate voltage or accept a shorter service life.
Size code B — 1411 footprint, 2.1 mm seated height
The manufacturer size code B maps to a 1411 (3528 Metric) case — 3.50 mm x 2.80 mm footprint with a maximum seated height of 2.10 mm. This is a standard low-profile tantalum case; the PCB land pattern follows the EIA-535BAAC specification.