SMD fuse for 125 V board-level protection
The Littelfuse 0451008.MRSN is an 8 A fast-blow SMD fuse from the NANO²® 451 series, rated for 125 V AC and DC circuits with a breaking capacity of 50 A at rated voltage. Housed in a 2-SMD square end block package measuring 6.10 mm x 2.69 mm x 2.69 mm, it mounts directly to the PCB surface — no through-hole or cartridge-style body.
Current, voltage, and let-through energy
Rated 8 A continuous with a cold DC resistance of 0.0077 ohms — the voltage drop at rated current is under 62 mV, negligible for most 125 V rails. The melting I²t of 20.23 A²s defines the energy needed to open the element; this figure is used to coordinate with downstream semiconductor protection and to size the trace width on the PCB.
Approvals and compliance
Carries CSA, METI, and UR approvals — accepted in North American and Japanese equipment without additional agency review.