ST2R507B

Overview

The ST2R507B is a surface-mount inrush current limiter manufactured by Littelfuse Inc. It features a nominal resistance of 2.5 Ohms with a tolerance of ±20%. The device supports a maximum steady-state current of 7 Amperes and has a physical length of 17.78 mm (0.700 inches). This component is designed for circuit protection against high initial surge currents.

Feature Summary

• Provides effective limitation of inrush current during power-up phases
• Utilizes a compact surface-mount package suitable for automated assembly
• Engineered to protect sensitive electronic components from thermal stress

Applications

• Power supply input stages
• AC/DC converter circuits
• Battery charging systems

Procurement Notes

Verify the specific Littelfuse part number ST2R507B against official distributor catalogs to ensure authenticity. Confirm that the received components match the specified 2.5 Ohm resistance and 7A current rating. Check for any manufacturing date codes or lot traceability information required for quality assurance records before integration into production lines.

Selection Notes

Select this component when a low-resistance, high-current inrush limiter is required for space-constrained designs. Ensure the application's peak surge current does not exceed the device's rated capacity of 7 Amperes. Consider the 2.5 Ohm nominal value for its impact on steady-state voltage drop and power dissipation within the target circuit topology.

Part Context

This component belongs to Littelfuse's family of inrush current limiters, which are specialized thermistors used to control transient currents. Unlike standard resistors, these devices exhibit negative temperature coefficient characteristics, allowing them to limit initial surges while maintaining low resistance during normal operation.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation. Consult Littelfuse technical support for equivalent alternatives.