1.5 F energy reserve for 6 V backup rails
The SCMR22H155PRBB0 is a 1.5 F supercapacitor rated at 6 V, part of the KYOCERA AVX SCM series. It stores enough charge to hold up a low-power microcontroller or RTC for seconds to minutes during a supply dropout, depending on the load current and the acceptable voltage droop. The 200 mOhm ESR at 1 kHz sets the ceiling on peak discharge current — a 6 V rail dropping to 3 V through this ESR can deliver about 15 A momentarily, but the real limit is the thermal rise from the I²R loss during the pulse. For sustained backup, the ESR governs the voltage sag at the load.
Tolerance and lifetime — design margin factors
The capacitance tolerance is 0%, +100% — typical for supercapacitors, where the actual value can be anywhere from 1.5 F to 3.0 F off the production line. The backup time calculation must use the minimum capacitance at end-of-life, not the nominal, to guarantee hold-up time across the full operating window. Rated lifetime is 1000 hours at 65 °C. At lower operating temperatures the lifetime extends significantly — roughly doubling for every 10 °C drop below the rated temperature. A 40 °C ambient gives an order-of-magnitude longer life than the 65 °C figure, but the datasheet's 1000-hour rating is the only guaranteed number. The upper limit matches the lifetime rating temperature; sustained operation above 65 °C accelerates the electrolyte dry-out and capacitance fade.
Through-hole radial can — PCB footprint
Packaged in a radial can with PC pin termination, 0.453" (11.50 mm) lead spacing. The through-hole mounting suits wave-solder assembly and provides a robust mechanical anchor for the relatively heavy component. Supplied in bulk packaging — no tape-and-reel, so the parts are loose in a bag or tube. This is typical for through-hole supercapacitors and means the pick-and-place requires a tube feeder or manual insertion.