2.5 A fast-blow in a 1206 footprint
The Littelfuse 1206SFF250F/32-2 is a 2.5 A fast-blow surface-mount fuse from the SFF series, rated for 32 VDC with a 50 A interrupting capacity at that voltage. The 0.14 melting I²t tells you this fuse opens quickly on a hard short but will tolerate the brief inrush of a 100 µF capacitor bank charging from a 24 V rail — the energy to blow the element is 0.14 A²s, so the pulse must exceed that integral to clear the fuse. The 1206 (3216 Metric) package is the standard footprint for board-mount fuses in this current class, and the 0.037 Ohm DC cold resistance means a 2.5 A load drops about 93 mV and dissipates 230 mW — negligible in most circuits but worth checking if the fuse sits in a tightly regulated 3.3 V rail where every millivolt of headroom matters.
Obsolete — sourcing through independent channels
Littelfuse lists the 1206SFF250F/32-2 as Obsolete. Sourcing this part now runs through independent distribution — surplus inventory, new-old-stock lots, and broker channels. The SFF series is a recognized UL 248-14 supplementary fuse line. The UL approval certifies the design meets the standard for overcurrent protection in equipment where the branch circuit is already protected. For a replacement search, the key parametric anchors are the 2.5 A current rating, 32 VDC voltage, fast-blow response, and the 1206 footprint — any candidate fuse must match these four constraints to drop into the same PCB land pattern and protect the same load.
Temperature grade and deployment context
In a 125°C engine-bay ECU or a -55°C satellite power conditioner, the fuse element's time-current curve shifts with temperature — the datasheet's derating guidance (not reproduced here) should be consulted for the actual trip point at the application's ambient. The 50 A breaking capacity at 32 VDC is adequate for most low-voltage DC power rails; at higher system voltages the interrupting rating may be lower, so confirm the fault current available at the fuse location. The surface-mount 1206 package is a common PCB layout footprint. Tape & Reel packaging is the typical supply format for volume production.