Hold current and voltage ceiling for a 0603 PTC
Rated for 200 mA hold current (Ih) at 25 °C ambient, this Littelfuse POLY-FUSE 0603L020YR trips at 500 mA (It) within 600 ms under fault. The polymeric PTC can interrupt up to 40 A of fault current, which covers most low-voltage rail shorts upstream of a current-limited supply. Initial series resistance is 550 mOhms minimum; after a trip event the resistance rises to 3.5 Ohms maximum — this post-trip value is the steady-state series resistance the load sees until power is cycled and the PTC resets.
0603 footprint and board integration
Surface-mount assembly on standard FR-4; the concave termination profile mates with the same land pattern as a standard 0603 resistor or capacitor — no special footprint required. Operating temperature range is -40°C to +85°C, covering commercial and most industrial ambient conditions. The hold current derates above 25 °C; at 85 °C the effective Ih drops to roughly 50% of the 25 °C rating — a design consideration for enclosures with internal heating.
Agency approvals and compliance documentation
Recognized by cURus and TUV — the two most common safety agency marks for polymeric PTCs in North American and European equipment. The approvals cover the device's function as a thermally-limited overcurrent protector under UL 1434 and IEC 60738-1.