Protection envelope and sourcing reality
The Littelfuse 1206SFF500F/32-2 is a 5 A fast-blow fuse in the SFF series, rated for 32 VDC with a 45 A breaking capacity at rated voltage. The 0.6 melting I²t means it clears quickly on high inrush events, but the fast-blow characteristic also means it may nuisance-open on repetitive surge currents near the I²t threshold. Littelfuse lists this part as obsolete. Sourcing runs through independent distribution channels; quantities and pricing are confirmed at RFQ against the BOM line.
Board-fit and thermal environment
The 1206 (3216 metric) SMT package — 0.126" x 0.063" x 0.043" — fits standard pick-and-place assembly with a 1206 footprint. The 0.018 ohm DC cold resistance keeps voltage drop low at rated current, but the resistance rises with temperature; derate the continuous current above 25°C per the Littelfuse SFF derating curve. The fuse element is sealed in the 1206 body — no outgassing or contamination path into the board assembly.
Approvals and compliance
UL recognized component — the fuse carries UL listing per the SFF series approval.