MS15 40004-A

Inrush Current Limiters (ICL) Overview

The Vishay Ametherm MS1540004-A is a Negative Temperature Coefficient (NTC) thermistor inrush current limiter belonging to the MegaSurge™ series. It features a nominal resistance of 40 Ohms at 25°C with a tolerance of ±25%. The component supports a maximum steady-state current of 4.1 A and has a recommended energy rating of 135 Joules. Its physical dimensions include a diameter of 0.670 inches (17.00 mm) and a lead spacing of 0.307 inches (7.80 mm). The device exhibits a low resistance at operating current of 280 mOhms.

Inrush Current Limiters (ICL) Feature Summary

• Utilizes NTC thermistor technology to provide high initial resistance that decreases as temperature rises, effectively limiting surge currents during power-up.
• Designed for repeated cycling applications, allowing continuous protection against inrush currents without permanent degradation.
• Features UL approval for safety compliance in electronic circuit protection.

Inrush Current Limiters (ICL) Applications

• Protection of capacitive loads in DC power supply circuits
• Inrush current limiting in AC/DC converter inputs
• Surge protection for general electronic equipment power stages

Inrush Current Limiters (ICL) Procurement Notes

Verify the specific suffix 'A' when ordering, as it may denote a particular packaging or variant configuration distinct from the base MS1540004 model. Confirm that the 40 Ohm resistance and 4.1 A current ratings align with the target circuit's peak inrush requirements. Ensure compatibility with the required lead spacing and mounting style for the final assembly.

Inrush Current Limiters (ICL) Selection Notes

Select this component based on the circuit's peak inrush current magnitude and the thermal capacity required to absorb the energy without overheating. The 40 Ohm initial resistance must be sufficient to limit the surge to safe levels for downstream components. Consider the steady-state current of 4.1 A to ensure the device does not exceed its thermal limits during normal operation.

Inrush Current Limiters (ICL) Part Context

This part belongs to the Vishay Ametherm MegaSurge™ series of inrush current limiters. These components are specifically engineered for robust performance in demanding electronic applications where sudden current spikes can damage sensitive circuitry. The series offers various resistance and current ratings to suit different power levels.

Inrush Current Limiters (ICL) Replacement Considerations

The MS1540004B is a verified substitute within the same series, offering identical electrical specifications including 40 Ohms resistance and 4.1 A current rating. Verify that any replacement matches the physical dimensions and lead spacing to ensure mechanical compatibility.