What this TPS-series tantalum does on the board
The molded package gives a consistent footprint for pick-and-place.
Sizing the decoupling bank with the ESR ceiling
At 100 µF and 250 mOhm, this cap's impedance at 100 kHz is dominated by the ESR, not the capacitive reactance. For a switching regulator output, parallel two or three of these to cut the effective ESR below 125 mOhm if the ripple current spec demands it. The B case code — 3.50 mm x 2.80 mm footprint, 2.10 mm seated height — fits the standard 1210/3528 metric land pattern. No via-in-pad needed; the anode and cathode terminations are on the short ends.
The TPS series is a broad production line, so allocation risk is low for standard values like 100 µF / 4 V.