ST2R018B

Overview

The ST2R018B is an NTC thermistor inrush current limiter from the Littelfuse ST series. It features a nominal resistance of 2 Ohms at 25°C with a tolerance of ±20%. The component supports a maximum steady-state current of 18 A and exhibits a hot resistance of 30 mOhms. Designed for PCB mounting, it utilizes a radial package with straight leads spaced 0.310 inches apart. The unit measures 1.201 inches in diameter and 0.35 inches in width, weighing approximately 12.3 grams.

Feature Summary

• Functions as an inrush current limiter to protect electronic circuits during power-up
• Utilizes negative temperature coefficient (NTC) thermistor technology for resistance variation
• Supports high steady-state current handling capabilities

Applications

• Power supply input protection
• Electronic equipment circuit protection
• Building and home automation systems

Procurement Notes

This product is officially classified as obsolete and no longer manufactured by Littelfuse. Availability is restricted, and distributors may not stock this item in all regions. Verification of part authenticity and condition is critical when sourcing from secondary markets due to the discontinuation status.

Selection Notes

Engineers should evaluate alternative components within the same ST series or newer Littelfuse generations due to the obsolete status of this specific part number. Compatibility checks regarding lead spacing, diameter, and thermal characteristics are necessary when designing replacements for existing layouts.

Part Context

The ST2R018B belongs to the ST series of inrush current limiters produced by Littelfuse Inc. This series is designed for circuit protection applications requiring robust surge suppression. The component is categorized under general-purpose circuit protection devices intended for industrial and consumer electronics.

Replacement Considerations

Public confirmed substitute part numbers include ST2R018BRA.