15 A fast-blow SMD fuse for secondary-side protection
The 0451015.NRL is a 15 A fast-blow surface-mount fuse from the Littelfuse NANO² 451 series, rated for 65 V AC and DC with a 50 A breaking capacity at rated voltage. Its 97.82 melting I²t and 0.0037 Ω cold resistance mean it clears a short quickly while keeping voltage drop low in normal operation — a fit for power input or DC rail protection on a board that sees up to 125 °C ambient.
What the ratings mean for the BOM line
The 15 A continuous rating at 65 V covers most low-voltage DC rails (12, 24, 48 V) and AC secondary circuits. The fast-blow response means it opens on a moderate overcurrent within milliseconds — no time-delay for inrush, so the load's start-up surge must stay below the I²t curve. Breaking capacity of 50 A at 65 V is adequate for secondary-side fault clearing in equipment fed by a limited transformer or PSU; a direct mains-fed circuit would need a higher interrupting rating.
Mounts in a 2-SMD square end block footprint (6.10 mm x 2.69 mm x 2.69 mm) — the same land pattern as the NANO² 451 family. The surface-mount body suits reflow soldering; the tape-and-reel packaging (Cut Tape option available) feeds pick-and-place without a changeover.
Approvals and compliance
CSA and UL recognized — the fuse carries the agency marks that most North American and Canadian equipment standards require for secondary overcurrent protection.