Littelfuse PolySwitch 1812L Series Resettable Fuse 30V DC 350mA

The Littelfuse PolySwitch 1812L Series Resettable Fuse is a miniature polymeric positive temperature coefficient (PPTC) device designed for reliable overcurrent protection in space-constrained electronic circuits. It automatically resets after the fault condition is removed and power is cycled, eliminating the need for manual replacement and providing long-term maintenance-free operation.

With a compact 1812 (4532 metric) surface-mount package, this component is ideal for densely populated printed circuit boards. It features a low holding current of 350mA, making it suitable for protecting sensitive low-power circuits from potentially damaging overcurrent events. The fuse trips at 750mA, providing a robust safety margin while responding quickly to faults with a trip time of just 0.15 seconds.

Rated for 30V DC applications, it can handle a maximum interrupt current of 40A, ensuring protection even under severe short-circuit conditions. Its operating temperature range extends from -40°C to +85°C, guaranteeing stable performance in harsh environmental conditions.

Key Features & Applications

• Automatic Reset: No need for manual replacement after a fault, reducing downtime and maintenance costs.
• Compact SMD Design: The 1812 case style is perfect for modern, miniaturised electronics.
• Fast Response: Trips in 0.15 seconds to protect sensitive components from damage.
• Broad Temperature Range: Reliable operation from -40°C to +85°C.
• High Interrupt Rating: Can safely interrupt currents up to 40A.

This resettable fuse is an essential component for safeguarding power supplies, battery packs, communication ports, and other critical circuits in consumer electronics, industrial controls, and telecommunications equipment.