1.25 A fast-blow in a 0603 footprint
The Littelfuse 04671.25NR is a 1.25 A fast-blow surface-mount fuse from the 467 series, packed in a 0603 (1608 metric) case. Rated for 32 VAC and 65 VDC, it handles the common low-voltage rails you see on control boards and telecom line cards. The breaking capacity is 35 A on the AC side and 13 A on the DC side — enough to clear a hard short on a typical 24 V or 48 V bus without the fuse casing rupturing.
What the ratings mean on the bench
The 0.0518 melting I²t figure tells you how much energy the fuse absorbs before it opens. For a 1.25 A fast-blow, that is a low threshold — it pops quickly on a moderate overcurrent, which is exactly what you want when protecting a sensitive load that cannot ride through a sustained fault. DC cold resistance is 0.051 Ohms. At 1.25 A, that is about 80 mV of voltage drop and 80 mW of self-heating — negligible in most circuits, but worth checking if your rail margin is tight and the fuse sits in a high-ambient spot. The operating temperature range is -55°C to 90°C. That covers the full industrial band and most automotive cabin environments, but if your fuse is near a hot MOSFET or regulator, the 90°C ceiling means you need to keep the local ambient below that or derate the current.
Active production, sourced to order
Approved by CSA and UL — the two agencies most commonly required for safety-listed overcurrent protection in industrial and commercial equipment. If your compliance checklist demands UL-recognized or CSA-certified components, this fuse checks both boxes.