What the 6.3 A rating and 50 A breaking capacity mean for your board
The 045106.3NR is a Littelfuse NANO²® 451 series fast-blow SMD fuse rated 6.3 A at 125 VAC and 125 VDC. The 50 A breaking capacity at rated voltage means it can safely interrupt a fault current up to 50 A without rupturing or sustaining an arc — adequate for secondary-side protection in low-power AC/DC supplies and DC rails where the available fault current stays below that threshold.
Lifecycle reality — obsolete, sourced through surplus channels
Littelfuse lists the 045106.3NR as obsolete. No official successor is recorded. No pin-compatible drop-in replacement from Littelfuse is documented; a board-level change may be required if migrating to an active series.
Package, mounting, and thermal envelope
Housed in a 2-SMD square end block package measuring 6.10 mm x 2.69 mm x 2.69 mm, the fuse is surface-mount compatible with standard reflow profiles. The DC cold resistance of 0.0096 ohms keeps voltage drop low at rated current.
Approvals and compliance documentation
The 045106.3NR carries CSA, cURus, and PSE agency approvals, qualifying it for North American and Japanese markets. The melting I²t of 9.17 A²s aids coordination with downstream semiconductor fusing requirements.