Fast-blow SMD fuse, 6.3 A, 125 V — Littelfuse NANO² 451
The 045106.3MR is a Littelfuse NANO²® 451 series surface-mount fast-blow fuse, rated 6.3 A continuous at 125 VAC or 125 VDC. The 50 A interrupting rating at rated voltage means it can safely clear a short-circuit fault up to that level without rupturing the package. Its melting I²t of 9.17 A²s characterises the energy needed to open the element — useful for coordinating with downstream semiconductor devices that have a lower surge-withstand capability. The DC cold resistance is 0.0096 Ω, so at rated current the I²R loss is under 0.4 W, well within the SMD package's thermal budget.
Obsolete — sourcing through independent channels
Littelfuse lists the 045106.3MR as obsolete. Approvals from CSA, PSE, and UL cover the major North American and Asian regulatory jurisdictions for equipment-level safety certification.
Housed in a 2-SMD square end-block package measuring 6.10 mm x 2.69 mm x 2.69 mm. The surface-mount footprint suits reflow assembly; the tape-and-reel packaging (TR) is compatible with standard pick-and-place feeders.