ESR and ripple current — the BOM-fit decision
The TPSB156M020R0500: The 500 mOhm ESR at 20 V and 15 µF sets the self-heating floor: at 0.5 A ripple current the internal power dissipation is 0.125 W, which the B case's 2.10 mm seated height must sink to the board without exceeding the 125 °C rating.
Package and footprint — what the pick-and-place needs
Molded 1411 (3528 Metric) B case, 3.50 mm x 2.80 mm footprint with a 2.10 mm max seated height — the 0.50 mm pitch pad layout is standard for this case code, and the ±20% tolerance means the capacitance at 20 V bias will sit between 12 µF and 18 µF, which the downstream regulator's phase margin must accommodate.