MICROSMD400LR-2

Overview

The MICROSMD400LR-2 is a polymeric positive temperature coefficient (PPTC) resettable fuse from the microSMD series, manufactured by Littelfuse Inc. It features a hold current of 4 A and a trip current of 8 A at a maximum voltage of 6 VDC. The device has a maximum resistance of 13 mΩ and a power dissipation of 0.8 W. It operates within a temperature range of -40°C to +85°C and utilizes a 1210 (3225 Metric) surface mount package with dimensions of 3.43 mm in length, 2.8 mm in width, and 0.48 mm in height.

Feature Summary

• Provides overcurrent protection through automatic resistance increase during fault conditions
• Enables circuit recovery without manual replacement after fault clearance
• Designed for compact surface-mount integration in space-constrained applications

Applications

• Portable electronic devices requiring low-voltage circuit protection
• Battery-powered equipment needing overcurrent safeguarding
• Consumer electronics utilizing surface-mount assembly processes

Procurement Notes

Verify component authenticity through authorized Littelfuse distributors or certified suppliers. Confirm that the received parts match the specified part number MICROSMD400LR-2 and exhibit the correct 1210 package dimensions. Ensure compliance with RoHS standards as indicated in official documentation. Request manufacturer test reports to validate electrical parameters such as hold current and resistance values before production use.

Selection Notes

Select this component when designing circuits operating at 6 VDC or lower with steady-state currents up to 4 A. Consider the 1210 footprint compatibility with existing PCB layouts. Evaluate thermal management requirements given the 0.8 W power dissipation rating. Compare against alternative PPTC fuses if higher voltage ratings or different current thresholds are required for specific application constraints.

Part Context

This component belongs to the microSMD family of resettable fuses, which are characterized by their small form factor and surface-mount construction. The series offers various current ratings while maintaining consistent voltage specifications and package styles. These devices utilize polymer technology to provide reliable protection in modern electronic assemblies where traditional fuses are impractical due to size or reusability requirements.

Replacement Considerations

MICROSMD400F-2 serves as a direct functional substitute within the same series offering identical electrical characteristics and package dimensions.