MF-RM012/240-2

Overview

The Bourns MF-RM012/240-2 is a polymeric resettable fuse from the MF-RM series, designed for line voltage circuit protection. It features a hold current of 120 mA and a trip current of 300 mA at ambient temperature. The device supports a maximum voltage of 240 VAC and can withstand a maximum fault current of 1.2 A. It exhibits a typical resistance of 3 Ohms and requires 15 seconds to trip under rated conditions. The component operates within a temperature range of -20°C to +85°C and utilizes a radial through-hole package with an 8.3 x 3.8 mm footprint.

Feature Summary

• Polymeric positive temperature coefficient construction for automatic circuit recovery
• Radial lead configuration suitable for standard through-hole PCB mounting
• Line voltage rating capability for AC power supply applications
• Compact disc-shaped body design for space-constrained layouts

Applications

• Overcurrent protection in AC power supply input stages
• Secondary side protection for consumer electronics devices
• Circuit safeguarding in industrial control equipment
• Protection for battery charger circuits

Procurement Notes

Verify that the specific suffix '-2' corresponds to the cut tape or reel packaging format as defined by Bourns documentation. Confirm the radial lead spacing matches the target PCB footprint requirements. Ensure the operating environment temperature remains within the specified -20°C to +85°C range to maintain reliable tripping characteristics. Cross-reference the datasheet for any specific handling precautions related to polymeric materials during soldering processes.

Selection Notes

Select this component when a resettable fuse is required for 240 VAC line voltage applications with a 120 mA hold current requirement. Compare the 3 Ohm resistance against acceptable voltage drop constraints in the circuit design. Evaluate the 15-second trip time against the sensitivity needs of the protected load. Consider the radial package dimensions relative to available board space compared to alternative series options.

Part Context

This part belongs to the MF-RM series of line voltage PTC resettable fuses manufactured by Bourns Inc. The series provides robust overcurrent protection for AC mains-powered equipment. The MF-RM family offers various hold current ratings to suit different power levels while maintaining consistent voltage ratings and physical form factors for standardized design integration across multiple product lines.

Replacement Considerations

Direct substitutes include other MF-RM series variants with identical voltage ratings but different hold currents, such as MF-RM016/240-2 or MF-RM040/240-2, provided the current specifications align with the application requirements. Verify that any replacement maintains the same radial package style and lead spacing to ensure mechanical compatibility without PCB redesign.