B57127P509M301

Overview

The B57127P509M301 is a leaded and coated NTC thermistor disk from the P27 series, designed for inrush current limiting. It features a nominal resistance of 5 Ohms at 25°C with a tolerance of ±20%. The component has a diameter of 30.5mm (1.2 inches) and supports a maximum steady-state current of 20A. It carries UL certification under standard 1434.

Feature Summary

• Leaded and coated disk construction for robust mechanical stability
• Negative temperature coefficient behavior for passive inrush current suppression
• UL certified insulation system ensuring safety compliance

Applications

• Power supply input stages
• Industrial drive systems
• Inverter circuits

Procurement Notes

Verify the specific part number suffix to confirm resistance value and current rating. Ensure the package type matches bulk distribution requirements. Confirm that the thermal time constant and steady-state current capabilities align with the target circuit's operational demands before finalizing procurement.

Selection Notes

Select this component based on the required 5 Ohm resistance and 20A steady-state current capacity. Consider the 30.5mm diameter for physical space constraints. Verify that the application environment stays within the specified operating temperature range and that the leaded mounting style is compatible with the PCB layout.

Part Context

This component belongs to the EPCOS B57127P0***M301 series of inrush current limiters. These devices are manufactured by TDK Electronics and are widely used in power electronics for protecting sensitive components during startup phases. The series offers various resistance values to suit different current ratings.

Replacement Considerations

Compatible substitutes include B57127P100M301, B57127P709M301, and B57127P209M301. When replacing, ensure the new part matches the required resistance, current rating, and physical dimensions to maintain circuit performance and mechanical fit.