Bulk capacitance for a 4 V rail — what the 220 µF and 100 mOhm ESR tell you
The TPSD227K004R0100: 220 µF at 4 V with 100 mOhm ESR — this is the bulk cap you reach for when a low-voltage rail needs ripple smoothing and transient hold-up. The 100 mOhm ESR keeps the self-heating under control at ripple currents typical of a 4 V buck converter; the 220 µF provides enough charge to cover a few hundred nanoseconds of load step before the regulator loop catches up.
That means it can sit next to a hot processor in an avionics bay, survive an engine-bay thermal cycle, or stay reliable in a downhole tool at 125°C ambient. The molded case and tantalum construction hold the capacitance and ESR across that band — no derating curve gymnastics at the cold end.
No NRND flag, no EOL notice — you can design this into a new board without worrying about a last-time-buy window closing.
2917 (7343 Metric) — footprint that fits a standard power-stage layout
The 2917 (7343 Metric) case is a common tantalum footprint — 7.30 mm x 4.30 mm, seated height 3.10 mm max. It mates with the standard land pattern for this size code, so you can drop it into an existing power-stage layout without a board spin. The molded body gives good mechanical stability during reflow and under vibration.