TRF250-120UST-B-0.5

Ptc Resettable Fuses Overview

The Littelfuse TRF250-120UST-B-0.5 is a polymeric PTC resettable fuse from the PolySwitch TRF250 series, designed for through-hole PCB mounting. It features a radial disc package with a 5.00 mm lead spacing. Key electrical parameters include a hold current of 120 mA and a trip current of 240 mA. The device supports a maximum voltage of 60 VDC (250 VAC interrupt) and a maximum current of 3 A. Initial resistance is typically 4 Ohms minimum, rising to 16 Ohms maximum after tripping. It operates within a temperature range of -40°C to +85°C and has a time-to-trip characteristic of approximately 1 second.

Ptc Resettable Fuses Feature Summary

• Polymeric self-resetting circuit protection utilizing positive temperature coefficient technology
• Radial through-hole construction suitable for wave soldering assembly processes
• Automatic restoration of conductivity following fault condition removal

Ptc Resettable Fuses Applications

• Building and home automation circuits
• Innovative circuit protection solutions
• General electronic equipment overcurrent protection

Ptc Resettable Fuses Procurement Notes

Verify component authenticity by cross-referencing the manufacturer part number Littelfuse TRF250-120UST-B-0.5 with official datasheets. Confirm RoHS compliance status and MSL level 1 classification. Ensure the supplier provides valid traceability documentation matching the specific suffix B-0.5 for accurate packaging and handling specifications.

Ptc Resettable Fuses Selection Notes

Select this component when a 120 mA hold current and 60 VDC rating are required for through-hole applications. The 1-second trip time distinguishes it from standard variants like the TRF250-120 which may have different response characteristics. Ensure the 5 mm lead spacing fits the target PCB footprint and that the 16 Ohm max resistance meets circuit impedance constraints.

Ptc Resettable Fuses Part Context

This part belongs to the Littelfuse PolySwitch TRF250 series of resettable fuses. It serves as a reusable alternative to traditional one-time fuses in low-voltage DC applications. The UST suffix indicates specific thermal or packaging variations within the broader TRF250 family, differentiated from standard bulk-packaged counterparts by its specific form factor and assembly compatibility.

Ptc Resettable Fuses Replacement Considerations

Direct substitutes include TRF250-120T-R1-B-0.5 and TRF250-120S-B-0.5. Verify that replacement parts maintain identical hold current, voltage ratings, and physical dimensions before integration into existing designs.