1 A fast-blow SMD fuse — obsolete, last-time-buy sourcing
The 0451001.MR is a Littelfuse NANO²® 451 series surface-mount fuse rated 1 A at 125 V AC/DC with a fast-blow response time. The 50 A interrupting capacity at rated voltage means it clears a short-circuit fault up to that level without rupturing the package — adequate for secondary-side protection in low-power AC/DC supplies and DC rails where the available fault current stays under 50 A. Littelfuse lists this part as obsolete. Sourcing runs through independent surplus and broker channels; availability and pricing are confirmed at RFQ against the BOM quantity.
Housed in a 2-SMD square end block package measuring 6.10 mm x 2.69 mm x 2.69 mm, the 0451001.MR mounts directly to the PCB footprint for the NANO² 451 series. The 0.153 Ohm DC cold resistance produces an I²R voltage drop of 153 mV at rated current — a factor when the fuse sits in a low-voltage rail where every millivolt of headroom matters. Tape & Reel packaging suits automated pick-and-place assembly.
Approvals and compliance documentation
CSA, PSE, and UL agency approvals are listed — the UL recognition covers the 125 V AC/DC rating and 50 A interrupting capacity for North American panel and equipment builds. PSE certification supports export into the Japanese market. RoHS and REACH compliance documentation is available from the manufacturer's archive for this obsolete part.