40 mA hold current in a 0603 footprint
The Littelfuse 0603L004YR is a polymeric PTC resettable fuse from the POLY-FUSE 0603L series, rated for 40 mA hold current and 120 mA trip current at 24 V max. In a 0603 (1608 metric) concave surface-mount package, it trips in 1 second at 20 A max fault current.
Resistance and temperature envelope
Initial resistance (Ri) is 4 Ohms minimum; after tripping, the post-trip resistance (R1) rises to 40 Ohms maximum — the ratio tells you the voltage drop across the device in the latched state is about 1.6 V at 40 mA, which is well within the 24 V rail budget.
Active production and approvals
Littelfuse lists the 0603L004YR as Active in its product lifecycle. It carries cURus and TUV agency approvals, so it is accepted in North American and European equipment without additional safety agency review.