Hold current and trip characteristics
The 0603L035YR is a Littelfuse POLY-FUSE® series polymeric PTC resettable fuse in a 0603 concave surface-mount package. It holds 350 mA continuously (Ih) and trips at 750 mA (It), with a maximum trip time of 100 ms at fault current. Rated for a maximum voltage of 6V and a maximum fault current of 40 A, this PTC is sized for low-voltage rail protection — USB VBUS, battery lines, or any 3.3V/5V supply that needs a resettable overcurrent guard without a fuse replacement. The initial resistance is 200 mΩ minimum (Ri), rising to 1 Ω maximum after a trip event (R1). The post-trip resistance is the key number for downstream voltage drop: at 350 mA load, expect under 0.35 V drop after reset, but budget the full 1 Ω ceiling if the part has cycled.
The concave termination profile means the solder fillet wicks up the end cap — standard reflow profile for 0603 chip components applies. Surface-mount mounting with tape-and-reel or cut-tape packaging.