The ±20% tolerance is standard for tantalum electrolytics and covers the full operating temperature range; a 4.7 µF part at 16 V derates to roughly 3.3 µF at 125°C due to the voltage coefficient of tantalum dielectrics, so the BOM should budget for the effective capacitance at the circuit's worst-case temperature.
ESR and ripple current handling
For a 4.7 µF output filter on a 500 kHz buck converter, the ripple current is typically under 100 mA, so the self-heating from 3.1 Ohm ESR stays below 30 mW — well within the part's thermal budget. If the application draws higher ripple current, the ESR causes a temperature rise that accelerates aging; the 125°C rating provides headroom.
Package fit and footprint decision
The case size is 1411 (3528 Metric) and also listed as 1210 — the 3.50 mm x 2.80 mm footprint with a seated height of 1.20 mm. This dual footprint listing means the land pattern matches both standard 1411 and 1210 pads, so the same PCB layout accepts this part or a ceramic X5R/X7R in a 1210 package without a board spin. The size code T on the body identifies the case dimensions at a glance during inspection.
The molded construction and general-purpose feature set mean no special screening, but the temperature rating itself is the selection gate for harsh-environment BOMs.