PTC resettable fuse for low-voltage board protection
The Littelfuse 1206L035/15YR is a polymeric PTC resettable fuse from the POLY-FUSE® 1206L series, designed to protect low-voltage circuits by tripping when current exceeds the hold threshold and automatically resetting after the fault clears. Rated for a maximum voltage of 15 V and a maximum fault current of 100 A, this part is suited for USB ports, battery packs, and other 5–12 V DC power rails where a resettable overcurrent device is preferred over a one-time fuse.
Hold current, trip current, and time to trip
The hold current (Ih) is 350 mA maximum at 25 °C — the device will not trip below this steady-state current. The trip current (It) is 750 mA, meaning the PTC begins to switch to a high-resistance state when the load exceeds roughly double the hold rating. Typical time to trip at 25 °C is 100 ms, fast enough to protect against short circuits without nuisance tripping on inrush from a capacitive load. After tripping, the post-trip resistance (R1) rises to a maximum of 1.2 Ω, limiting fault current; initial resistance (Ri) is a minimum of 300 mΩ, keeping voltage drop low during normal operation.
The 1206L035/15YR is listed as Obsolete by Littelfuse, meaning the manufacturer no longer produces it. Sourcing is through independent distribution channels; availability and pricing are confirmed at the time of RFQ against your BOM quantity.