750 mA fast-blow protection for tight board-level circuits
The Littelfuse 0451.750MRL is a 750 mA fast-blow surface-mount fuse from the NANO²® 451 series, rated for 125 V AC and DC circuits with a 50 A interrupting capacity at rated voltage. The fast-blow response clears quickly on overcurrents above the rating, making it suited for protecting sensitive electronics where a brief overload could damage downstream silicon. A melting I²t of 0.185 defines the energy needed to open the fuse element — useful for coordinating with inrush currents from capacitive loads or for ensuring the fuse does not nuisance-blow on normal startup transients.
Surface-mount footprint and environmental range
Housed in a 2-SMD square end block package measuring 6.10 mm x 2.69 mm x 2.69 mm, the 0451.750MRL mounts directly to the PCB and reflows alongside standard passive components. The DC cold resistance of 0.245 Ohms is low enough that self-heating at rated current stays within the package's thermal limits.
Approvals and compliance coverage
The 0451.750MRL carries CSA and UL approvals, confirming it meets North American safety standards for overcurrent protection in board-level circuits.