ESR and ripple current budget
For a 22 µF cap on a 500 kHz buck output, the ripple current is typically 200-400 mA RMS; at 900 mOhm that dissipates 36-144 mW, which raises the internal temperature by 5-15 °C above ambient — well within the 125 °C ceiling, but the derating curve in the datasheet should be checked for sustained operation near the upper limit.
Voltage derating for tantalum reliability
Tantalum capacitors are derated to 50-60% of rated voltage for field reliability. At 6.3 V rated, the recommended DC bias is 3.2-3.8 V. A 5 V rail is too close to the rating — use a 10 V or 16 V rated part instead to avoid field failures from voltage surges or inrush.
Suitable for avionics black boxes, downhole instrumentation, and engine-bay ECUs that see thermal cycling from cold soak to under-hood heat. The 1206 case and molded construction handle vibration and moisture common in those environments.