Obsolete Littelfuse SFP 2.5 A fuse — sourcing and ratings
The 1206SFP250F/32-2: It is rated for 32 VDC with a breaking capacity of 50 A at rated voltage, and carries UL recognition.
Breaking capacity and cold resistance
The 50 A breaking capacity at 32 VDC means the fuse can safely interrupt a fault current up to 50 A without rupturing or sustaining arc — sufficient for most low-voltage DC circuits in this current class. The DC cold resistance is 0.07 Ohms, which at 2.5 A yields an I²R loss of about 0.44 W, well within the 1206 package's dissipation capability. Melting I²t is 1.19 A²s — this is the energy required to open the fuse element. For inrush-prone loads (capacitive inputs, motor starts), the I²t must exceed the energy of the transient to avoid nuisance opening.