B57127P109M301

Overview

The B57127P109M301 is a leaded and coated NTC thermistor disk from the P27 series, designed for inrush current limiting. It features a nominal resistance of 1 Ohm at 25°C with a tolerance of ±20%. The component supports a maximum steady-state current of 30A and exhibits a hot resistance of 13 mOhms. With a diameter of 30.5mm (1.2 inches) and a lead spacing of 7.50mm, it utilizes PCB mounting. The device holds UL certification under standard 1434.

Feature Summary

• Provides effective inrush current limitation during power-up phases
• Features robust leaded and coated disk construction for durability
• Supports high steady-state current handling capabilities

Applications

• Power supply input stages
• Transformer primary circuits
• Motor drive protection systems

Procurement Notes

Verify the specific suffix M301 to confirm lead length and spacing compatibility with your PCB footprint. Ensure the thermal environment allows for adequate heat dissipation given the 30A steady-state rating. Cross-reference the UL file number for regulatory compliance requirements in your target market. Confirm that the 1 Ohm cold resistance aligns with your circuit's startup current specifications.

Selection Notes

Select this variant when a low initial resistance of 1 Ohm is required to minimize voltage drop during normal operation while still limiting peak surge currents. The 30A steady-state capacity suits applications with higher continuous loads compared to higher-resistance variants. Consider the 30.5mm diameter for mechanical stability and thermal mass requirements in industrial or automotive contexts.

Part Context

This component belongs to the EPCOS B57127P0***M301 series of NTC inrush current limiters. The series offers various resistance values ranging from 0.5 Ohm to 10 Ohm, all sharing the same 30.5mm disk geometry and M301 lead configuration. It serves as a protective element against high transient currents in electronic equipment.

Replacement Considerations

Direct substitutes within the same series include B57127P059M301 (0.5 Ohm), B57127P209M301 (2 Ohm), and B57127P0709M301 (7 Ohm). These share identical physical dimensions and mounting characteristics but differ in electrical performance. Verify that the alternative resistance value meets your specific inrush limiting and steady-state current requirements.