Overview

The MF-MSMF030-2 from Bourns Inc. is a surface-mount polymer PTC resettable fuse designed for overcurrent protection in low-voltage electronic circuits. As part of the MF-MSMF series, it uses a polymeric positive temperature coefficient element that rapidly increases in resistance when the current exceeds its hold rating, effectively limiting fault current and protecting downstream components. Once power is removed and the fault condition clears, the device cools and automatically resets, eliminating the need for fuse replacement. These resettable fuses are commonly used on supply rails and I/O lines in consumer, computing, industrial, and communication equipment where compact size, low series resistance, and multiple-trip capability are required.

Applications

• Overcurrent protection on DC power rails in consumer electronics (set-top boxes, game consoles, media players)
• USB and other I/O port protection in PCs, printers, and peripheral devices
• Battery-powered equipment such as handheld instruments, portable medical devices, and data loggers
• Industrial control modules, PLC I/O cards, and sensor interface boards
• Telecom and networking equipment, including routers, switches, and VoIP hardware
• Protection of LED drivers and low-voltage lighting control circuits

Alternatives & Replacement

Depending on stock levels, lead time, or specific design constraints such as hold current, trip current, and package size, alternative resettable fuses may be considered. Within the same Bourns family, options like MF-MSMF010-2 or MF-MSMF050-2 can sometimes be used if their electrical ratings and footprints align with your design requirements. Cross-vendor parts from Littelfuse and others may also be suitable in new designs or redesigns where a layout change is acceptable.

Recommended alternatives:

• Bourns Inc. MF-MSMF010-2 (Functional Equivalent – check current ratings and derating curves)
• Bourns Inc. MF-MSMF050-2 (Redesign Required – different current characteristics)
• Bourns Inc. MF-PSMF010X-2 (Redesign Required – different series and parameters)
• Bourns Inc. MF-FSMF035X-2 (Redesign Required – different footprint/ratings)
• Littelfuse Inc. 1812L020PR (Redesign Required – different package and specs)
• Littelfuse Inc. 1206L035YR (Redesign Required – different package and specs)

Engineering note: Always confirm replacement suitability by checking the detailed datasheets for hold and trip current, maximum voltage, time-to-trip, I_max, operating temperature range, and physical package. Ensure that PCB footprint, pin orientation, and thermal/derating behavior are compatible with the original design before implementing any substitute.