ST2R515B

Overview

The ST2R515B is a power thermistor designed for inrush current limiting applications. Classified as a Negative Temperature Coefficient (NTC) device, it functions by exhibiting high resistance at ambient temperatures to restrict initial surge currents and low resistance during normal operation to minimize power loss. This component is manufactured by Littelfuse Inc. and serves as a critical protection element in electronic circuits susceptible to transient overcurrent events.

Feature Summary

• Provides automatic inrush current limitation through variable resistance characteristics
• Reduces thermal stress on sensitive downstream components during power-up
• Enables reliable circuit protection without requiring external control logic

Applications

• Power supply input stages
• AC-DC converter circuits
• Motor drive protection systems

Procurement Notes

Verify the obsolete status of this specific part number before initiating procurement actions. The manufacturer indicates that production has ceased, rendering the item non-cancelable and non-returnable. Sourcing may require secondary market channels or inventory checks rather than direct factory allocation. Confirm end-of-life documentation with authorized distributors to ensure compliance with project lifecycle requirements.

Selection Notes

Engineers should evaluate alternative NTC inrush limiters from the same product family or newer generations due to the discontinuation of the ST2R515B. Selection criteria must include steady-state current ratings, maximum allowable voltage, and resistance tolerance specifications. Ensure that substitute components match the physical footprint and thermal dissipation requirements of the original design to maintain system integrity.

Part Context

This component belongs to the broader category of power thermistors utilized for circuit protection. It is distinct from standard resistive elements due to its temperature-dependent conductivity. The device is intended for integration into printed circuit boards where managing startup transients is essential for preventing component failure and ensuring stable electrical performance across varying environmental conditions.

Replacement Considerations

Consult Littelfuse official documentation for confirmed substitute part numbers within the ST series or equivalent NTC thermistor families. Verify that any replacement maintains identical electrical parameters and mechanical dimensions to ensure seamless integration into existing designs without redesigning the PCB layout.