220 µF, 4 V, 50 mOhm — the bulk tantalum for low-voltage rails
The TPSY227K004R0050: The 50 mOhm ESR is low for a standard MnO2 tantalum in this case size (2917 / 7343 Metric). Lower ESR means the capacitor can handle higher ripple current without self-heating — useful on a switching regulator output where the AC component of the inductor current flows through the cap.
Package and temperature range
The ±10% tolerance is tight enough for output filtering where the regulator's feedback loop expects a known capacitance window.