6.8 µF, 35 V, D case — the board-fit story
The TPSD685K035R0400: The 400 mOhm ESR is the spec that governs ripple current handling in a DC-DC output filter — at 100 kHz, the self-heating from ripple current is I² × 0.4 Ω, so the allowable ripple current is limited by the 125 °C max operating temperature and the board's ability to sink heat from the D case. The 0.50 mm pitch pad layout is standard for this size — the anode pad is the larger of the two, and the cathode end is marked by a stripe on the body. Reflow profile follows the standard JEDEC MSL-3 moisture sensitivity for molded tantalum; a 24-hour bake before rework is needed if the bag seal is broken. The -55 °C to 125 °C operating range covers military and industrial temperature bands — the capacitance change over temperature is typically +10% at -55 °C and -10% at 125 °C relative to the 25 °C value, so the 6.8 µF minimum at the cold end is actually higher than the nominal. The 35 V rating is at 85 °C; above that, derate to 2/3 of rated voltage at 125 °C.
The molded tantalum construction is RoHS-compliant per KYOCERA AVX standard material declarations. No AEC-Q200 automotive qualification is listed for this general-purpose series — for under-hood or chassis applications, specify the TPS series with automotive screening.