10 A fast-blow SMD fuse for board-level protection
The 0451010.MRSN is a Littelfuse NANO²® 451 series surface-mount fuse rated for 10 A continuous current at 125 V AC or DC. Its fast-blow response time clears overcurrents quickly, making it suitable for protecting sensitive circuits where a time-delay characteristic could allow damage before the fuse opens. The 35 A breaking capacity at the rated voltage means it can safely interrupt fault currents up to that level without rupturing — adequate for most secondary-side DC rails and low-power AC branch circuits.
Package and board-fit
Housed in a 2-SMD square end block package measuring 6.10 mm x 2.69 mm x 2.69 mm, this fuse occupies a compact footprint for dense PCB layouts. Surface-mount construction with a DC cold resistance of 0.0056 ohms minimizes voltage drop and I²R heating at rated current — the fuse runs cool in normal operation.
Approvals and compliance
Carries CSA, METI, and UR approvals, confirming acceptance in North American and Japanese regulatory frameworks for safety-critical overcurrent protection. The melting I²t of 26.46 A²s gives a measure of the energy let-through during clearing — useful for coordinating with downstream semiconductor ratings in a protection scheme.