Board-fit note for the 1.75 A hold-current PTC
The Littelfuse 1206L175PR is a polymeric PTC resettable fuse from the POLY-FUSE 1206L series, designed to protect low-voltage DC power rails from overcurrent faults while resetting automatically once the fault clears and power is cycled. Its 1.75 A hold current (Ih) is the maximum steady-state current the device can carry without tripping at 25°C ambient — size the protected circuit so the normal operating current stays below this threshold. At 3.5 A trip current (It) the PTC resistance rises sharply, limiting fault current within 500 ms typical — the downstream load sees a high-impedance state until the fault is removed and power is recycled. With a 6 V maximum voltage rating and 100 A maximum fault current, this part fits USB bus protection, battery pack output, and portable device power inputs where the rail stays under 6 V.
Surface-mount integration and temperature envelope
Mounted in a 1206 (3216 metric) concave package, the 3.25 mm x 1.65 mm footprint with 1.80 mm max thickness suits dense PCB layouts in portable and handheld electronics. Initial resistance is 20 mOhms minimum, rising to 90 mOhms maximum after tripping — the post-trip resistance adds series loss in the circuit until the device resets.
Compliance and approvals for global shipment
Carries cURus and TUV approvals, qualifying the part for equipment shipped into North American and European markets without additional component-level certification.