7 A fast-blow fuse in a compact SMD package
The Littelfuse 0451007.MR is a NANO²® 451 series surface-mount fuse rated 7 A at 125 V AC and 125 V DC. The fast-blow response clears overcurrents quickly, and the 50 A breaking capacity at rated voltage means it safely interrupts short-circuit faults up to that level without rupturing.
Sourcing an obsolete part
Littelfuse has marked the 0451007.MR as Obsolete. Sourcing is through independent distribution channels; availability and pricing are confirmed at RFQ against the BOM quantity.
What the ratings mean for the board
The 10.32 melting I²t gives a measure of the energy required to open the fuse — useful for coordinating with downstream components and ensuring the fuse clears before the PCB trace or semiconductor junction exceeds its surge rating. DC cold resistance is 0.009 Ohms, so the voltage drop at 7 A is under 63 mV — negligible in a 125 V rail. Approvals from CSA, PSE, and UL mean the fuse is accepted in North American and Japanese regulatory jurisdictions — a signal for compliance-driven BOMs.