Molded tantalum, 0.68 µF, 35 V — ESR trade-off
The TPSA684K035Y6000: A molded tantalum capacitor in the TPS series, this 0.68 µF part is rated for 35 V with a maximum ESR of 6 Ohm — the ESR is the dominant loss term at ripple frequencies above a few hundred kHz, so the part is better suited to bulk decoupling and hold-up than to high-frequency filter poles where a ceramic would offer lower impedance.
Military temperature range — -55 to 125 °C
Rated for the full -55 to 125 °C operating band — this is the military/defence temperature grade, not the narrower industrial range. The tantalum dielectric's capacitance stability with temperature is tighter than X7R ceramics across this span, and the molded construction resists moisture ingress better than uncoated ceramics.