What the 4 A rating and fast-blow response mean for your circuit
The 0467004.NRHF is a Littelfuse Series 467 surface-mount fuse rated 4 A with a fast-blow response time. Fast-blow means the fuse element is designed to open quickly on overcurrents just above the rating — it offers minimal tolerance for inrush spikes, so it is the right choice for circuits where the load current is steady and the fault path is low-impedance, not for capacitive or motor-start inputs that draw a brief surge at power-up. The 35 A breaking capacity at 32 V AC/DC tells you the fuse can safely interrupt a fault current up to that level without rupturing or sustaining an arc. If the available short-circuit current at the fuse location exceeds 35 A, this part is not a safe fit — step up to a higher-interrupting device in the same footprint.
0603 footprint and board-level integration
The 0603 (1608 metric) package measures 0.063" x 0.032" x 0.012" — a standard chip-size footprint that reflows on the same profile as 0402 and 0805 passives. The DC cold resistance of 0.00118 ohms means the voltage drop at 4 A is under 5 mV, negligible in a low-voltage rail. Operating temperature spans -55°C to 90°C, which covers most indoor and outdoor equipment but not engine-bay or high-temp industrial zones. If the ambient near the fuse exceeds 90°C, the 4 A rating must be derated per the manufacturer's curve — a common oversight when the fuse sits next to a hot regulator or power stage.
Approvals and compliance
UR (UL Recognized) means the fuse has been tested to UL 248-14 for supplementary protectors; CSA is the Canadian equivalent. No CE or UKCA marks are listed in the spec, so if the end product ships to the EU, verify the fuse's CE declaration separately. Littelfuse lists the 0467004.NRHF as Active on the lifecycle status — no NRND or EOL notice. That means it is still in regular production and available through franchised distribution.