2.5 F hold-up for a 5.5 V rail
The SCMS22F255PRBA0 is a 2.5 F supercapacitor from the KYOCERA AVX SCM series, rated at 5.5 V with an ESR of 180 mOhm at 1 kHz.
ESR and lifetime at 65°C
The 180 mOhm ESR at 1 kHz sets the charge/discharge efficiency. For a 2.5 F cap, that ESR produces an RC time constant of roughly 0.45 seconds — the cap delivers its stored energy quickly, but the I²R loss during a high-current pulse heats the cell. The rated lifetime is 1000 hours at 65°C; operating below that temperature extends life significantly, though the datasheet derating curve is the final word for a specific duty cycle. The through-hole radial can with 0.610" (15.50 mm) lead spacing and PC pin termination fits a standard 20.00 mm x 10.00 mm footprint on the board. Seated height is 23.50 mm max — check clearance against adjacent components or an enclosure lid.