Obsolete — last-time-buy window closed
The 0451012.MR: Sourcing now runs through independent surplus and broker channels. Availability is lot-specific and confirmed at RFQ; date-code provenance and traceability documentation should be verified before committing to a BOM line.
12 A fast-blow fuse, 65 V rating, 50 A breaking capacity
Rated 12 A continuous at 65 V AC or DC, this surface-mount fuse clears overcurrents with a fast-blow response — the melting I²t of 47.97 A²s defines the energy let-through before the element opens. For a 12 A rail, that I²t is low enough to protect downstream semiconductors from short-circuit thermal stress, but the 50 A breaking capacity at rated voltage means the fuse must see a prospective fault current below that ceiling; higher available fault current requires an upstream current-limiting device.
Surface-mount footprint 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 sits flat on the PCB with end-cap terminations — no through-hole leads, so the reflow profile must match the solder paste and the pad geometry on the board. Tape & Reel packaging supports automated pick-and-place assembly; the square end-block body is self-aligning during reflow, but the small 2.69 mm height means the fuse is not a candidate for hand-soldering touch-up without risk of thermal damage to the element.
Approvals and compliance baseline
CSA and UL approval agency listing means the fuse carries safety certification for North American and Canadian markets — UL 248-14 for supplemental fuses. RoHS and REACH compliance documentation is available from the manufacturer; the part is lead-free and does not contain the restricted substances under the current EU directives.