Hold current and trip threshold for the BOM line
The 1206L050/24WR is a Littelfuse POLY-FUSE® series polymeric PTC resettable fuse in a 1206 SMD package. Its 500 mA hold current (Ih) is the continuous current it passes without tripping under normal conditions, making it the primary selection parameter for the protection rail. The trip current (It) is 1 A — the threshold at which the device begins to switch from low resistance to high resistance, limiting fault current. The 100 ms typical trip time at 1 A means it responds fast enough to protect most downstream silicon from overcurrent damage.
Automotive-grade qualification and regulatory approvals
The 24V max voltage covers 12V automotive rails with margin for load-dump transients. Approvals from cURus and TUV confirm compliance with North American and European safety standards for overcurrent protection devices, supporting global BOM acceptance without separate agency review.
Package, footprint, and sourcing posture
The concave termination profile is standard for PTCs in this footprint and reflows on a standard Pb-free profile without special handling. Initial resistance (Ri) is 150 mOhms minimum, rising to 750 mOhms max after tripping (R1). The low Ri means minimal I²R loss at 500 mA — about 37.5 mW dissipation in the normal state.