400 F, 2.7 V, 2.2 mOhm — the energy buffer for high-current backup
The SCCY68B407SSBLE is a 400 F, 2.7 V supercapacitor from the KYOCERA AVX SCC LE series, packaged in a radial through-hole can with four PC pin leads. The 2.2 mOhm ESR at 1 kHz is the key parameter for pulsed discharge applications — it determines the instantaneous voltage drop under load and the I²R heating during charge/discharge cycles. A 400 F cell with sub-3 mOhm ESR supports peak currents in the tens of amperes without the terminal voltage collapsing below the load's minimum operating threshold. Operating temperature spans -40°C to 65°C, with a rated lifetime of 1000 hours at 60°C. The -10%, +30% capacitance tolerance is typical for high-capacitance supercapacitors — the +30% headroom means the actual capacitance at end-of-life may be higher than the nominal 400 F, which is a factor when sizing the backup duration at the cold end of the temperature range where capacitance drops.
Mechanical fit — radial can with four leads
Lead spacing is 0.886 inches (22.50 mm). The four-lead configuration reduces ESR by providing multiple parallel current paths into the electrode stack — the outer pair are the main current-carrying terminals, the inner pair serve as sense connections for balancing circuits in multi-cell stacks. The through-hole mounting requires a drilled PCB with 22.5 mm pitch holes; the can diameter dictates a minimum keep-out zone of 38 mm to allow for the vent and handling clearance.