The SCMR22D155PSBB0H is a 1.5 F supercapacitor rated at 5.4 V, part of the KYOCERA AVX SCM series. The 5.4 V rating means two cells in series can be used without an external balancing circuit on a 5 V rail — the voltage margin covers the full charge cycle without exceeding the per-cell limit. ESR is specified at 200 mOhm at 1 kHz. In a hold-up application, this ESR sets the initial voltage drop when the load switches from the main supply to the capacitor — a 1 A step draws 200 mV at the terminals before the capacitance starts to hold the rail. The radial through-hole package with 0.453" (11.50 mm) lead spacing fits standard 0.2" or 0.3" pitch prototyping grids and many PTH layouts. The 18.50 mm x 9.50 mm body with a seated height of 25.50 mm leaves clearance under low-profile enclosures.
Temperature and endurance — thermal budget for backup power
Rated for 1000 hours at 65°C. This is the accelerated life test condition; at 40°C ambient the expected lifetime extends significantly per the Arrhenius model, but the datasheet's 65°C figure is the one to use for warranty calculations in a 60°C cabinet. At the cold end, ESR rises — typical supercapacitor ESR at -40°C is 3-5x the 25°C value — so a circuit that must deliver pulse current at low temperature should budget for the higher drop.