The TPSD337M006H0045: That ESR figure is the key spec for a bulk decoupling or hold-up cap — it sets the ripple current capability and the self-heating under AC load. The D case (2917 / 7343 metric) footprint is a common size for power supply outputs and POL converters. The 3.10 mm seated height fits most board-to-board clearance envelopes under a mezzanine or above a low-profile heatsink.
KYOCERA AVX lists this part as Active. The TPS series is a mainstream molded tantalum line with broad distribution coverage. The -55°C to 125°C operating range covers industrial, telecom, and automotive under-hood ambient. No AEC-Q qualification is stated, but the temperature grade matches typical automotive-grade tantalum derating guidelines.
45 mΩ ESR — what it means for the circuit
At 45 mΩ, this cap handles ripple current well above the typical tantalum baseline. For a 100 kHz buck converter output, the ESR dominates the output voltage ripple — 45 mΩ at 1 A ripple gives 45 mV p-p, which is acceptable for most logic rails without a secondary LC filter. The ±20 % tolerance is standard for tantalum electrolytics. The actual capacitance at the 6.3 V rated voltage is closer to the nominal value than at lower bias, but derating to 50 % of rated voltage (3.15 V or lower) is recommended for best lifetime and to avoid surge failures.